PERLITE

Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian.
It occurs naturally and has the unusual property of greatly expanding when heated sufficiently.
It is an industrial mineral, suitable "as ceramic flux to lower the sintering temperature", and a commercial product useful for its low density after processing.

Perlites are small pebbles of natural glass which contain a small amount of occluded water, and are found in volcanic deposits.

EC / List no.: 603-442-8
CAS no.: 130885-09-5
AMORPHOUS ALUMINO SILICATE
dialuminum;dipotassium;disodium;dioxosilane;iron(3+);oxocalcium;oxomagnesium;oxygen(2-)
PERLITE

EC / List no.: 618-970-4
CAS no.: 93763-70-3
Amorpohous Alimina Silicate
Perlite, expanded

IUPAC names
Aluminiumsilikat
Amorpohous Alimina Silicate
dialuminiumtrioxide
Perlite
Perlite, Expanded
Perlite, expanded

Trade names
Filter aid, Harborlite|r 800S

Other names
amorphous alumina silicate
Expanded Perlite
Perlite

Perlite is an Amorphous mineral consisting of fused sodium potassium aluminum silicate, with variable chemical composition and 1% quartz Perlite uses and applications include: In abrasives, acoustical plaster and tile, wallboard, charcoal barbecue base, cleanser base, filter aids, metal foundries, refractory products; as packaging material; as soil conditioner; hydroponic agriculture substrate; lightweight concrete aggregates; wallfloor insulation; as filler in construction materials; as inert carrier for pesticidesfertilizers; in chemical, steel, and food industries

Perlite, obsidian, and pitchstone are volcanic glasses that differ in water content: obsidian, less than 2% H2O; perlite, 2–5%; and pitchstone, more than 5%.
The general range of composition (Bush 1973, p. 341) is 70–75% SiO2, and about 10–15% Al2O3.
The water content is critical to expansion, but obsidians with as little as 0·2% H2O are reported to have expanded satisfactorily.
Originally, perlite meant a glassy rock characterized by concentric cracks, but commercial usage includes any glassy rock (except pumicite) that can be expanded by heating to about 2000 °F (1100 °C).

Perlite is a substance that has many commercial and industrial uses.
Also known as volcanic glass, perlite is used in agriculture, shipping, medicine and a host of other applications.

What is Perlite?
Perlite is a volcanic rock mined in the United States, as well as other countries like Turkey.
The volcanic glass, or perlite, is formed when lava (molten rock) spews out of a volcano, and cools in a rapid manner.
Because of rapid cooling, water is trapped within the rock, and the lava forms into a glass-like structure.
Perlite contains 2 to 5 percent water and is a silicate rock, meaning it contains a "high percentage of silica (Si)"

Perlite in its crude state bears little resemblance to the expanded product once it has been processed.

Expanded - Milled Perlite
Typical Chemical Analysis (% by weight unless otherwise stated)
SiO2 74,0% - 78,0%
Al2O3 11,0 % - 16,0 %
Fe2O3 0,4% - 1,0%
TiO2 0,0% - 1,0%
MgO 0,0% - 1,0%
CaO 0,5% - 1,0%
Na2O 1,0% - 4,0%
K2O 1,0% - 5,0%
L.O.I. 2,0% - 6,0%

Please contact us for various mesh sizes, specs and applications.
We can also sell PERLITE ORE in Turkey.

USES
Perlite’s uses depend on the field of application:

Industry
Agriculture
Construction
Cryogenics: expanded perlite is an excellent insulator for low or very low temperature cryogenic systems. It is widely used in LNG (Liquefied Natural Gas) isolation tanks, noble gas tanks, oxygen, nitrogen, argon etc. in cryogenic state.
Mortars and refractory elements: perlite is used as an ingredient in low to medium temperature refractory elements (up to 850°C) and it is used to build and/or coat ovens, furnaces, etc., and as a bonding material for joining refractory pieces.
Isolation: passive fire protection. The manufacturing of mortars, plates and various accessories. Ceramic furnaces.
Filtration: one of the most common uses of expanded perlite is as a filtering agent. The expanded and processed ore is chemically inert, and does not transfer taste, colour or odour to the filtrate. There is a wide range of perlite filters for various products such as beer, wine, water, oils, chemicals etc.
Fire protection system petrochemical industry.
Substrates-peat: perlite can be mixed with all kinds of organic substrates, providing them with a distinct capacity to be well aerated. The structure of perlite remains unchanged over time and helps to regulate water consumption by acting as a reservoir.
Hydroponics: of all the materials used for soilless cultivation, expanded perlite is the most important. In fact, several studies have shown that outstanding crops can be achieved with perlite hydroponic systems.
Animal nutrition: perlite acts as a binding, anti-caking and coagulant agent. Due to its high absorption capacity, perlite is used to support and carry a wide variety of nutrients, fatty acids, vitamins and antibiotics used in the preparation of additives for animal feeds.
Gypsum: perlite is a basic ingredient in the development of new lightweight projected gypsum mortars.
Monolayer Mortars: perlite is a basic ingredient in the manufacturing of projectable monolayer finish mortars.

Perlit is used as a substrate agent in soil aeration, steel layering, advancement of hydration level of soil, spreading of fertilizer, as well as in enhancing the physical attributes of flower and pot soil.

WHY TO USE PERLITE IN AGRICULTURE?

»  Perlite ensures soil aeration and improves its drainage with over 90% porosity and around 60% aeration porosity.
»  Perlite provides economic irrigation. 
»  It does not carry weed seed or illness thanks to its inorganic structure.
»  Perlite does not cause saltiness and alkalization problems thanks to highly reduced amount of soluble ions contained.
»  It regulates the PH of the soil easily as it is neutral (PH=6.5-7.5). 
»  Thanks to its low heat conductivity, it minimizes the harmful effect of daily temperature changes on the plant.
»  In soilless agricultural activities, it ensures protection of its properties after sterilization offering 5-6 years of use life.   It provides early cultivation of yields. 
»  It prevents damage and loss at seedling roots. 
»  In order to eliminate the problems experienced in the greenhouse soils which gradually become exhausted, perlite use in soilless agricultural applications have increased over the recent years.

Perlite has been extensively used as a lightweight aggregate material in concrete or mortar. In expanded form perlite offers thermal insulation, fire resistance and other desirable properties when used in portland cement- or gypsum-based plaster. The authors review current applications, with particular reference to lightweight fibre-reinforced composites based on cement/gypsum plaster and perlite binder. The availability of local supplies of perlite has promoted interest in its use in India but progress has been hampered by a lack of local knowledge and Standards. A brief description is given of an ongoing research project examining the effect of litemix and fellite perlite aggregate on the properties of a plain gypsum plaster and a new water-resistant gypsum binder reinforced with glass fibre.

Gypsum perlite
Abstract
FIELD: construction.
SUBSTANCE: gypsum perlite contains a gypsum binder, such as a processed mechanically activated phosphogypsum ground to 5-40 mcm (active gypsum), hydrophobizated swollen sand, superplasticiser Melflux at the following ratio of components, wt %: active gypsum - 84.8-93.8%, hydrophobizated swollen perlite sand - 6-15%, superplasticiser - 0.2%.
EFFECT: improved heat insulation and strength properties at low prime cost.
1 tbl

 

Effect of expanded perlite on the mechanical properties and thermal conductivity of lightweight concrete
Author links open overlay panelOzkanSengulaSenemAzizibFilizKaraosmanoglubMehmet AliTasdemira

Abstract
The main objective of this study is to provide more data on the effects of expanded perlite on the mechanical properties and thermal conductivity of lightweight concrete.
In the experimental program, mixtures were prepared by partially replacing natural aggregate by expanded perlite and as a result, unit weights of lightweight concretes in fresh state varied between 700 and 2000 kg/m3. Water to cement ratio was kept constant in all mixtures. Compressive strength, modulus of elasticity, water absorption and capillarity coefficient of the mixtures were determined. Thermal conductivity of the specimens was also obtained. Test results show that the compressive strength and modulus of elasticity decreases with increasing in perlite content. Water absorption and sorptivity coefficient, however, increase with the higher perlite contents. The test results indicate that the thermal conductivity is substantially improved with the use of perlite and a strong relationship between thermal conductivity and unit weight is obtained.



 

Properties

Perlite softens when it reaches temperatures of 850–900 °C (1,560–1,650 °F).
Water trapped in the structure of the material vaporises and escapes, and this causes the expansion of the material to 7–16 times its original volume.
The expanded material is a brilliant white, due to the reflectivity of the trapped bubbles.
Unexpanded ("raw") perlite has a bulk density around 1100 kg/m3 (1.1 g/cm3), while typical expanded perlite has a bulk density of about 30–150 kg/m3 (0.03–0.150 g/cm3).

Typical analysis
70–75% silicon dioxide: SiO2
12–15% aluminium oxide: Al2O3
3–4% sodium oxide: Na2O
3–5% potassium oxide: K2O
0.5-2% iron oxide: Fe2O3
0.2–0.7% magnesium oxide: MgO
0.5–1.5% calcium oxide: CaO
3–5% loss on ignition (chemical / combined water)[3]

Sources and production

Perlite is a non-renewable resource. The world reserves of perlite are estimated at 700 million tonnes.

The confirmed resources of perlite existing in Armenia amount to 150 million m3, whereas the total amount of projected resources reaches up to 3 billion m3.
Considering specific density of 1.1 ton/m3 confirmed reserves in Armenia amount to 136 million tons.

Other reported reserves are: Greece - 120 million tonnes, Turkey, USA and Hungary - about 49-57 million tonnes. 

Perlite world production, led by China, Turkey, Greece, USA, Armenia and Hungary, summed up to 4.6 million tonnes in 2018.

Perlites are small pebbles of natural glass which contain a small amount of occluded water, and are found in volcanic deposits.
When smashed and softened by heat, the water vaporizes, leaving behind enlarged hollow spheres.
These are again smashed, and give a filter aid of very irregularly shaped particles whose bulk density ranges 0.05–0.10 g/mL (3–6 lb/ft3).
This bulk density is between one-tenth and one-fifth of many bleaching clays. 

As with other filter aids, be prudent and make a full-scale trial in working conditions to assess the full value—economic and technical—of any perlite grade chosen.

 

Uses
Because of its low density and relatively low price (about US$50 per tonne of unexpanded perlite), many commercial applications for perlite have developed.

Construction and manufacturing
In the construction and manufacturing fields, it is used in lightweight plasters, concrete and mortar, insulation and ceiling tiles.
Perlite may also be used to build composite materials that are sandwich-structured or to create syntactic foam.

Perlite filters are fairly commonplace in filtering beer before it is bottled.

Small quantities of perlite are also used in foundries, cryogenic insulation, and ceramics (as a clay additive).
Perlite is also used by the explosives industry.

Aquatic filtration
Perlite is currently used in commercial pool filtration technology, as a replacement to diatomaceous earth filters.
Perlite is an excellent filtration aid and is used extensively as an alternative to diatomaceous earth.
The popularity of perlite usage as a filter medium is growing considerably worldwide.
Several products exist in the market to provide perlite based filtration.
Several perlite filters and perlite media have met NSF-50 approval (Aquify PMF Series and AquaPerl) , which standardizes water quality and technology safety and performance.
Perlite can be safely disposed of through existing sewage systems, although some pool operators choose to separate the perlite using settling tanks or screening systems to be disposed of separately.

Biotechnology
Due to thermal and mechanical stability, non-toxicity, and high resistance against microbial attacks and organic solvents, perlite is widely used in biotechnological applications.
Perlite was found to be an excellent support for immobilization of biocatalysts such as enzymes for bioremediation and sensing applications.

Agriculture
In horticulture, perlite can be used as a soil amendment or alone as a medium for hydroponics or for starting cuttings.
When used as an amendment, it has high permeability and low water retention and helps prevent soil compaction.

Cosmetics
Perlite is used in cosmetics as an absorbent and mechanical exfoliant.

 

Estimated perlite consumption by application
Fraction Use
53% building construction products
14% horticultural aggregate
14% fillers
8% filter aid
11% other
 

What is Perlite?
Perlite is a volcanic glass that is heated to 1,600 degrees F. (871 C.)
whereupon it pops much like popcorn and expands to 13 times its former size, resulting in an incredibly lightweight material.
In fact, the end product weighs only 5 to 8 pounds per cubic foot (2 k. per 28 L.). 
The super heated perlite is comprised of tiny air compartments.
Under a microscope, perlite is revealed as being covered with many tiny cells that absorb moisture on the exterior of the particle, not inside, which makes it particularly useful in facilitating moisture to plant roots.
While both perlite and vermiculite aid in water retention, perlite is the more porous and tends to allow water to drain much more readily than vermiculite.
As such, it is a more suitable addition to soils utilized with plants that do not require very moist media, such as cactus soils, or for plants which generally thrive in well-draining soil.

Perlite is a form of volcanic glass (SiO2) that is mined all over the world. Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an industrial mineral and a commercial product useful for its low density after processing.

Perlite is mined using open pit methods such as ripping or blasting, or both. If the perlite is soft and friable, brecciated or extensively jointed, ripping is employed with significant cost savings. Blasting is required where perlite cannot be readily broken using rippers, but care must be taken to achieve fragmentation without production of excessive fines or oversized material.

Horticultural Perlite
While both perlite and vermiculite aid in water retention, perlite is the more porous and tends to allow water to drain much more readily than vermiculite. As such, it is a more suitable addition to soils utilized with plants that do not require very moist media, such as cactus soils, or for plants which generally thrive in well-draining soil.

Horticultural perlite is made by exposing perlite to heat, which causes the trace water contained in the perlite to expand, "popping" the perlite like popcorn and expanding it to 13 times its former size, resulting in an incredibly lightweight material. In fact, the end product weighs only 5 to 8 pounds per cubic foot. The superheated perlite is comprised of tiny air compartments.

Under a microscope, perlite is revealed as being covered with many tiny cells that absorb moisture on the exterior of the particle, not inside, which makes it particularly useful in facilitating moisture to plant roots. The result is a very lightweight, white stone-like substance. Perlite is prized for its moisture retention and aeration properties. It is naturally sterile and has a neutral pH.

Expanded Perlite: Description
Expanded perlite is a mineral product obtained by expansion of raw perlite. Perlite is a siliceous glass-like volcanic mineral. It is hard and brittle and expands up to 20 times its original volume depending upon the mineral source.
Raw perlite is milled and expanded by controlled rapid heating, which causes water molecules to escape from the mineral. This causes a popping sound, similar to a popcorn’s pop.
Expanded perlite is a chemically inert, non-toxic, and stable material with excellent thermal, audio, and electrical insulation properties. It is primarily utilized in the construction industry for insulation, in the horticulture industry as soil aggregates, and in the beverage industry for food contact filtration applications.
Physical characteristics of expanded perlite makes it an ideal option for usage for filtration purposes. Perlite filter aids are inert, lightweight, and do not impart any taste or odour when used for filtering liquids. They are highly soluble in organic acids. Thus, perlite filter aids are useful for various industrial filtration purposes.
The European Union recently approved the usage of expanded perlite as an additive in animal feed. Expanded perlite is employed in various industries such as pharmaceuticals, paints & coatings, and chemicals
Consumption of beer, juices, wine, etc. has increased. This is boosting the usage of expanded perlite, since it is used in the processing of beer, juices, and wine. This trend is expected to drive the market for expanded perlite in the near future.

Expanded perlite is used in various products in the personal care industry. It is inert and eco-friendly. Thus, it is useful in cosmetic as well as food-grade products.
Expanded perlite is used as an abrasive in cosmetic products such as soaps, face wash, scrubs, and shower gels. It also used in dental care products such as toothpastes.
The personal care products industry is well developed and has been expanding significantly in Asia Pacific and North America. This provides lucrative opportunities for the expanded perlite market.

 

What is perlite?
Perlite is a lightweight granular material that’s white in colour. It looks and feels like little bits of polystyrene but is actually made from expanded volcanic glass, heated to 1000°C until it ‘pops’ (like popcorn) to many times its original size. It’s lightweight, sterile, and easy to handle, and is long-lasting. It’s neither alkaline nor acidic.

Perlite’s expanded nature makes it extremely porous, so it can absorb water, but it also improves drainage, so is ideal to mix into compost to ensure water drains freely. Perlite is particularly useful in plant propagation, including taking cuttings and sowing seeds. Other materials that perform similar functions are vermiculite, grit and sharp sand.

Perlite helps aid drainage at the same time as retain water. Therefore you can use it in a number of ways:

Use perlite to aid drainage
Succulents and other plants sensitive to moist soil benefit from having perlite added to the potting compost. The perlite will trap air in the compost and encourage water to drain through, ensuring the plant’s roots will never sit in damp soil. Mix perlite with compost at a ratio of around 1:4. Do this before planting to ensure an even mix.

Use perlite when taking cuttings
Perlite can aid water retention in compost, which can help improve the chances of your cuttings taking root. To do this you need a compost that’s specifically designed for cuttings (with a finer texture and lower nutrient content than general use multi-purpose compost). Mix in perlite at a ratio of 50:50, fill the pots, water thoroughly and then allow the compost mix to drain for several hours before inserting your cuttings.

Cuttings can also be rooted in perlite on its own. Moisten the perlite and fill a polythene bag around a third full. Prepare softwood or semi-ripe cuttings by cutting just below a leaf joint and removing the leaves on the lower half to two-thirds of the cutting. Insert the bare lower part of the shoot into the perlite, fill the bag with air and seal the top. After several weeks, roots should start to form. Once roots are well developed, the cutting can be taken out and potted up in compost.

Use perlite in seed sowing
Mix perlite into seed and cuttings compost at a ratio of 50:50 to create a moist environment perfect for delicate seedling roots. A fine layer of perlite is also excellent for covering seed that needs light to germinate because the perlite lets light through whilst still keeping the seed moist and aiding germination.

 

Perlite is not a fertilizer, and has no nutritional or microbial value to plants or soil. Its benefits are derived solely from keeping the soil structure loose and light.

What perlite is: an inorganic, non-toxic, lightweight soil amendment.

Also known as expanded pyrite, perlite is a mined volcanic rock that is mixed into many industrial building products for stability, such as masonry construction, loose-fill insulation, cement, and plaster.

ike all other volcanic rocks, perlite is also pretty heavy and dense in its natural form. Perlite typically contains the following ingredients:

70-75% silicon dioxide
Aluminum oxide
Sodium oxide
Potassium oxide
Iron oxide
Magnesium oxide
Calcium oxide
3-5% Water
Since it is a naturally occurring mined mineral, perlite is a nonrenewable resource. The major producers are Greece, US, Turkey, and Japan.

It is a relatively cheap mineral and is often used for industrial purposes like construction and in the manufacture of plasters, masonry, and ceiling tiles.

But of special interest to us here is the use of perlite in gardening and hydroponics.

And for that, the hard mineral glass needs to be processed into the light, white colored, plasticky stuff that resembles styrofoam, confusing many a rookie gardener about its origin and purpose!


 

The processed perlite that we see in gardening mixes is basically “volcanic popcorn.” That is a very literal description.

Since perlite glass is rich in water, it pops when heated to very high temperatures, exactly like popcorn. So the processed perlite balls are created by crushing natural perlite glass and then baking them in industrial ovens.

To complete the transformation, crushed perlite needs to be heated quickly to 900 degrees Celsius (around 1650 degrees Fahrenheit). The mineral structure is softened by the heat, allowing the water trapped inside to expand into steam in a bid to escape.

The process leads to expansion of the crushed pieces of the mineral. It is not usual for perlite pieces to expand between 7 and 16 times their original size and volume, creating those lightweight faux-styrofoam balls.

The foamy balls have a lot of porous openings inside them and are clean, sterile and generally stable. It can hold its shape with ease in the soil without crumbling.

Significance of Perlite for Gardening
There are several reasons why perlite is such a useful additive to gardens and hydroponic setups. They mainly stem from its unique physical and chemical properties:

Perlite is physically stable and retains its shape even when pressed into the soil.
It has a neutral pH level
It contains no toxic chemicals and is made from naturally occurring compounds found in soil
It is incredibly porous and contains pockets of space inside for air
It can retain some amount of water while allowing the rest to drain away
These properties allow perlite to facilitate two critical processes in soil/hydroponics, which are essential for plant growth:

Aeration
All plant cells need oxygen, even those that are underground. The green parts up top are capable of creating it during photosynthesis.

But down below, the root system has to absorb it from the soil. Aerating the soil allows little pockets of air to remain, which helps with the growth of strong root systems.

Draining
Without water, no living thing can survive. But when it comes to plants, excess water in the soil can lead to drowning.

In this situation, the root system is starved of oxygen, causing eventual death. Proper drainage is crucial to allow empty air spaces to remain in the soil.

Adding perlite to the soil improves its drainage capabilities, as it has excellent filtering and water draining capabilities. The presence of all those pores allows most of the excess water to drain off.

And those air pockets also mean that perlite is great for root systems as well. When the soil gets packed down, the air pockets are lost. But since perlite is a harder mineral, it retains its shape, keeping those air pockets around for the roots.

Perlite vs. Vermiculite
Vermiculite

Perlite is directly comparable to another mineral additive called Vermiculite. Both have overlapping functions and help with soil aeration and seed starting.

Vermiculite also comes from some kind of rocks and expands in the same popcorn fashion like perlite. But vermiculite has a stronger expansion potential.

Perlite has more air porosity than vermiculite, and better drainage effects as well. Vermiculite, on the other hand, retains water much better than perlite.

Perlite is better suited for succulent plants, while vermiculite is better for tropical plants that need more moisture retained in the soil.

They both have their uses, and many experts tend to combine these two minerals in their soil mixes.

Perlite vs. Diatomaceous Earth
Diatomaceous Earth

Diatomaceous earth is also a mineral additive, available in a fine powder form. It is commonly referred to as DE.

Diatomaceous earth is used more for pest control than anything else in gardening. It also has high water retention abilities. But since it is a powder, it doesn’t help much with aeration.

Diatomaceous earth is not really a contender against perlite in any conceivable way. Both additives can be used together, for their respective benefits to the soil.

Pros and Cons of Perlite
Pros
Excellent for aeration of roots
Very stable and inert structure
Helps improve drainage
Cheap and easily available
Useful for hydroponics and gardening
Cons
Finer grades are affected by airflow/winds
Does not retain water
Contains no nutrients
Tends to float in excess water
Give off dust. So wear a mask to protect your exhalation when working with perlite

Perlite is an excavated mineral rock that is mixed with potting soil to help manage aeration and drainage for potted plants. The mineral is light-weight and porous creating air pockets within the soil that alleviate stress on roots. Perlite has been shown to help maximize root growth while lessening stress of drainage management for gardeners with plants kept in containers. Simply mix Perfect Plants Perlite with a multi-purpose potting mix or seed starter before planting. Perfect Plants Perlite comes in a 13x15" heavy duty, re-sealable bag — perfect for storage or later use.

The lightweight mineral prevents soil from compacting and "suffocating" the roots.
It allows proper aeration of the soil so that excess water and toxins can drain appropriately.
Perlite pieces loosen dense parts of the soil which allow room for roots to expand and absorb essential nutrients.
Since perlite is a mineral it will not decompose and advantageously it carries a neutral pH balance. This means it will match the pH balance of your soil when combined, instead of change it.

Expanded perlite is employed in the filtration & process aid applications in mining, water treatment processes and gas drilling activities. In oil fields, the product has usages in thermal insulation, aeration of soil and as a soil aggregate. Increasing drilling activities coupled with technological progressions will augment the expanded perlite market revenue. The product is used for filtering liquids in food & beverage and pharmaceutical industry as the product has inert nature, no taste, odor or color is imparted. It is recognized as a safe material by food safety regulatory bodies. Favorable trends associated with food & beverage industry is going to catapult the product demand in upcoming years.
 

The expanded perlite market share may be affected by availability of substitute materials. Various alternatives such as barite, polymeric foam and diatomaceous rock can be used instead of the product in many construction applications. However, in horticulture sector, substitutes such as vermiculite, cellulose, wood chips and peat can be used for performing various applications. T
 

DRAINAGE
• Perlite Decreases the Risk of Over-Watering Which Lessens the Risk of Root Disease.
• It Assists in Flushing Toxins Away While Holding Water Directly Where Roots Can Access.

AERATION
• Perlite Does Not Compact in Soil and Allows Roots to Expand to Their Full Potential.
• Perlite Will Regulate Soil Conditions During Weather Extremes.

SUSTAINABILITY
• Perlite Does Not Decompose Making it a Suitable Match for Container Plants.
• Although It Has No Nutritional Value, The Porous Nature of Perlite Can Hold Nutrients in Place for Roots to Absorb.

How perlite is made?
A natural volcanic glass, perlite is typically made from the hydration of obsidian. The chemical made up is seventy to seventy-five percent silica or silicon dioxide; the remaining twenty to twenty-five percent is a mix of aluminum oxide (Al2O3), oxides of sodium, potassium, iron, magnesium, and calcium, and moisture (1).

To create the perlite we are familiar with, the gray to black obsidian rock is mined, crushed into smaller fragments, and then heated to very high temperatures. Once temperatures reach 850-900 ℃ the perlite becomes soft. Water trapped inside the rock vaporizes and tries to escape, expanding the rock to more than 10 times its original volume and changing the color or perlite to white. An extremely similar process to making popcorn. 

The resulting expanded perlite is a lightweight material full of tiny little air pockets; it is clean, sterile, and resists compaction. The pockets on the outside absorb water, blocking moisture from entering into the center of the perlite pieces.

Gardening: Perlite can be added to soilless mixes to improve drainage and aeration, providing more oxygen to plant roots. It is also added to gardens as a soil additive to improve soil structure. Perlite also helps reduce soil compaction in clay soils. It is used as a standalone product to germinate seeds, root cuttings, and anchor/support root systems in hydroponic gardening setups. Epsoma is a great option for perlite and other gardening needs. Purchase it on Amazon here.
Construction: Perlite is used as loose fill material in hollow concrete blocks or masonry walls for insulation.
Filtration: Perlite is increasingly being used to filter solids out of liquids in many applications. It is used to filter beer before it’s bottled to remove sediment and is used to filter stormwater runoff from roads and highways.
Manufacturing: Perlite is also used as an ingredient in lightweight concrete and plasters, ceiling tiles, and acoustical sprays to name a few.
Types of perlite
After heating and expansion, horticultural perlite is separated into four different grades based upon the particle size: super coarse, coarse, medium, and fine grade.  

Super coarse perlite has particles ranging in size between ¼ and 3/32” with a water holding capacity of 19%. Creates the best porosity for drainage and aeration but isn’t as popular in gardening because of the particle size.
Coarse perlite ranges in size between 3/16 and 3/64”, with a 34% water holding capacity. Considered an all-purpose grade it is a good balance of drainage and water holding capacity. Due to its size, it doesn’t blend well with garden soil but makes a great media for succulents and orchids.
Medium grade perlite is a middle ground between the coarse and fine grades ranging in size between ⅛” and 1/32”. It has a 46% water holding capacity and is best to use alone as growing media for potted plants and potted seedlings or as an ingredient in potting mixes with other components.
Fine grade perlite has the smallest particle size, with pieces between 1/16 and 1/128”. With a water holding capacity of 52%, it works well for rooting cuttings and starting seeds.
Pros and cons for gardening use
As with so many other products, perlite has both its advantages and disadvantages as a growing media. In this case, the advantages far outweigh the downfalls boosting its popularity in the horticulture industry.

Pros:
Its sterile nature makes it highly suitable for starting seeds. There is little risk of root rot or damping off (2).
Naturally contains minerals needed for plant growth.
A non-toxic substance that doesn’t require rinsing like some other growing media does prior to use.
Neutral pH doesn’t need to be adjusted, nor will it adjust the overall pH when mixed with other components.
It can be used alone or mixed with other media to create potting mixes.
Great for seedling germination or plant propagation as the particles allow for plants to be pulled from the perlite without damage to the root systems when it’s time for transplanting.
Reusable year after year since it doesn’t decompose.
Low-cost option, perlite is cheaper than sand per cubic foot, costing about $4 or $5 per cubic foot.
Easily available and simple to manufacture.
Cons:
Water can drain away quickly. Perlite holds water in the nooks found on its large surface area but since it’s made of amorphous volcanic glass it doesn’t hold it tightly. 
Being so lightweight, perlite can be blown away and tends to float in excess water.
Nonrenewable resource. Although more readily available than peat moss, it isn’t considered renewable like coconut coir.
Dust can create respiratory problems and eye irritation. When working with perlite make sure to take precautions by wearing goggles and a mask to reduce dust exposure.
 

Perlite is one of nature’s most versatile and efficient minerals.
Its unique characteristics of being lightweight, sterile, insulating, and fireproof make it an excellent choice for such diverse applications as:

CONSTRUCTION
FILTRATION
HORTICULTURE
INDUSTRIAL
INSULATION
ENVIRONMENTAL

Perlite in Construction
Perlite is a versatile and sustainable mineral that is mined and processed with a negligible impact on the environment. And the green community recognizes perlite-enhanced products—like lightweight insulating concrete roof decks—as a high-performance solution drawn from a natural material of nearly unlimited supply throughout the world.

Construction Uses
Lightweight concrete & plaster
Loose fill & slab insulation
Fireproofing sprays
Chimney fill
Interstitial floors
Acoustical sprays & ceiling tiles
Texturizing agent
Fire-rated door cores
Blast panels
Tile, mortar and grout

Research claims that more than 50 percent of expanded perlite worldwide is used by the construction industry.
Perlite plays an important role in a wide variety of construction-related uses including: as an aggregate in lightweight insulating concrete and plaster; as a loose fill insulation material for concrete masonry blocks, cavity walls, in residential homes; and in a variety of specialty applications including fireproofing sprays, chimney fills, interstitial floors, acoustical sprays, etc

LIGHTWEIGHT INSULATING CONCRETE
Lightweight Perlite Insulating Concrete offers architects, engineers, and building owners several important benefits:

Superior thermal performance with high insulating values
Non-combustible with superior fire ratings
Lightweight and durable
Smooth monolithic slope-to-drain surface
Roofing material can be nailed or glued
Meets UL and FM wind uplift criteria
An innovative hybrid technology improves cellular concrete
Realize savings in time, labor, and materials
 

Perlite for Horticulture
When perlite ore is expanded or “popped” by rapid, controlled heating, it expands up to 15 times its original volume and takes on a foam-like cellular appearance – essentially clusters of microscopic glass bubbles, creating a porous structure. This physical transformation makes expanded perlite an extremely effective aggregate for use in horticultural growing mixes – or, by itself, as a medium in hydroponic growing and as a rooting medium

The primary role of expanded perlite in soilless growing mixes is aeration when added to peat moss, composts, coir and other water-holding aggregates. The porous surface of expanded perlite provides room alternately for both air and water in the mixes – each needed for vigorous root growth. Different sizes of perlite are produced for this purpose, offering growers various amounts of air space after drainage. Usage rates by volume vary from 5% to 40% for potting mixes, and as high as 75% to 100% in green roofs and hydroponics applications. Perlite use is increasing in agricultural and turf grass applications to break up compacted soils and retain water in dry climates.

THE BENEFITS OF PERLITE AS INSULATION
When perlite ore is expanded by exposure to rapid, controlled heating, it grows up to 20 times its original volume and takes on a foam-like cellular internal structure — essentially clusters of microscopic glass bubbles. This physical transformation makes expanded perlite an extremely efficient, low density insulator.
 

As detailed below, perlite is inorganic and non-combustable, and the loose-flowing nature of expanded perlite is ideal for filling odd-shaped spaces.

MASONRY FILL PERLITE
Expanded perlite provides a quick, inexpensive and permanent method for insulating masonry walls. Depending upon design conditions, reductions in heat transmission of 50 percent or more can be obtained when perlite loose fill is used in the hollow cores of concrete block or cavity type masonry walls. Perlite is a non-combustible, industrial mineral yielding superior dynamic thermal performance.

CRYOGENIC/HIGH TEMPERATURE INSULATION
Super-cold cryogenic fluids such as hydrogen and helium are normally stored in double-walled vessels with perlite-filled annular spaces.

OTHER INSULATION APPLICATIONS
Perlite insulation is an inorganic product that does not support combustion, or rot, nor does it provide a habitat for rodents. It is ideal for use under concrete slabs, in chimneys and in high-temperature applications such as pizza ovens and rocket stoves.
 

Perlite for Filtration
The physical character of expanded perlite bubbles lends itself to a variety of special purposes – including use as a filter aid separating small solid particles from liquids

Lightweight expanded perlite bubble structures are milled and classified using strictly defined processes to produce perlite filter aids with specific flow characteristics. The various grades utilize the jagged interlocking structures (see image right) to create billions of microscopic channels between the filter aid particles to produce optimum flow rates and clarification abilities for a wide variety of applications.

THE BENEFITS OF PERLITE AS A FILTER AID
Perlite filter aids are lightweight, inert, impart no taste or odor to liquids being filtered, and are virtually insoluble in mineral and organic acids at all temperatures. Solubility in strong alkaline solutions varies depending on temperature and contact time.

Without using a filter aid the solid particles in the liquid will soon accumulate on filtering surfaces and block them.

A perlite filter aid makes a filtering layer (cake) that transfers the actual filtering from the septum to the whole mass of filter aid. Filtration occurs in the tiny pores formed by the fine particles of filter aid.

Volume-Based Pre-coat Filtration
Perlite filter aids provide users with a lightweight material choice. Perlite filter aid grades provide the user with a density advantage from 20 to 50% over other types of filter aids. Perlite filter aid dry density ranges from 100 to 200 kg/m3 (6 to 12 lb/ft3), and the filter cake density range is 100 to 270 kg/m3 (7 to 17 lb/ft3). In contrast, other filtration materials produce equal performance filter cakes in the range of 230 to 420 kg/m3 (15 to 25 lb/ft3).

Expanded perlite provides larger volumes with low bulk density compared to other filter aids. Experience in a variety of applications has shown that most filter aid users can economically switch to perlite from other pre-coat filter aids without sacrificing performance.

Usable With Standard Equipment
Perlite filter aids can be used with either pressure or vacuum filtration equipment. Perlite generally replaces other filter aids on a one-to-one volume basis – for example; a cubic measure of perlite will replace the same volume of other filter aids. Selection of the optimum grade and dosage may require plant or laboratory filtration tests.

Flow Rates of Grades
Perlite filter aid grades from various manufacturers range from 0.2 – 6 Darcies. (The Darcy is a common unit of flow rate for filter aids.) A material with a permeability of one Darcy passes 1 milliliter per second per square centimeter of a liquid of 1 centipoise viscosity (approximately that of water) through a cake 1 centimeter thick at a differential pressure of 1 atmosphere.

The higher flow grades are especially applicable to use with highly viscous liquids such as syrup, resins or gelatinous slurries. Productivity, clarity and flow rates may be increased through the use of perlite filter aid grades. These traits are accomplished during the liquid’s path through the channels created by the jagged, interlocking particles.

Easy Cake Release
Additional benefits of perlite filter aids come at the end of the filter cycle. Perlite filter cakes remain porous and do not compact. Filter cakes built up under pressure release easier when perlite is used. This release facilitates cleaning, potentially reduces manpower requirements, and increases productivity. The lower weight of perlite filter cakes may also reduce disposal costs.

Inert Nature of Perlite
Perlite filter aids are both sterile and inert and are used for filtering liquids in the beverage, food and pharmaceutical industries. No tastes, colors or odors are imparted, and, subject to meeting the standards listed in the Food Chemicals Codex (published by the United States’ National Academy of Sciences), are deemed safe for their intended use. Note: The Food Chemicals Codex is regarded as a source of information on the quality and purity of food grade substances, and is regarded as authoritative by many government agencies throughout the world.

Approval for the use of perlite as an additive in animal feeds was recently extended in the European Union. Generally, spent filter aid cakes from wineries, breweries or other food-related industries may be added to animal feed. Such practices reduce the environmental footprint of those industries as well as reducing disposal costs for the used material. Approval for this application in the United States comes from the Association of American Feed Control Officials (AAFCO).

USE BY INDUSTRY:
Perlite filter aids have gained acceptance in almost every industry concerned with the separation of liquids and solids, and even gasses and solids. The following list, although not all-inclusive, gives an indication of the many applications where perlite filter aids are being utilized due to their low density, availability, performance, economy and environmental footprint:

Food Processing:
juices
beers
wines
sweeteners
vegetable oils
wastewater treatment

Pharmaceuticals:
enzymes
antibiotics
Epsom salt

Industrial:
water treatment
sizings
oil & solvent recovery
greases
Chemicals:
inorganic & organic chemicals
resins
polymers
brine
adhesives
fertilizers
waste disposal

Paint & Coatings:
waxes
oils
varnish
gums
shellac
wastewater treatment
Environmental:
stormwater filtration
ecology embankments
media filter drains

 

PERLITE IN SOUND INSULATION:

When it comes to noise protection in buildings, both sound-absorbing and sound-blocking (or soundproofing) materials come to mind.
When it comes to noise protection in buildings, both sound-absorbing and sound-blocking (or soundproo ng) materials come to mind.
Each off ers unique properties that make them suitable for speci c applications.

Processes that Govern the Absorption of Sound by Acoustic Materials
First, in porous materials, sound energy is transformed into heat by the viscous forces at work when sound propagates through materials.
Second, sound is dissipated by frictional forces when acoustic materials are set into vibration by the incident sounds.

Types of Noise
Airborne Noise – When airborne noise strikes a fl oor or ceiling, the surface is set to vibration by the fl uctuating pressure of the sound waves. Th is vibration is what radiates sound into the air on the other side.
Impact Noise – Impact noise is caused by an object striking or sliding on a fl oor, such as footsteps, moving furniture or a door slamming. It can also be caused by an appliance, such as a dishwasher or shower, which transmits its vibration to the building structure.

How Perlite Works as a Sound Absorption/ Blocking Material
Th e characteristic cellular structure of perlite and the successive air compartments hinder the propagation of sound waves, rendering it an ideal fi ller for sound-blocking and sound-absorbing applications.
When used as a  filler, sound waves can be consumed and absorbed by multiple levels due to the combination of an interconnected pore structure and cavity resonance sound absorption structure, resulting in a higher performance, sound absorption/blocking material

Perlite in Sound Insulation Applications

Applications
Th e versatile nature of expanded perlite allows it to be used in the manufacturing process of both sound-blocking and sound-absorbing products globally.

Sound-Absorbing Perlite-Based Products –
Expanded perlite is traditionally used as a primary constituent in the production of lightweight sound insulating panels and ceiling tiles. 
The intrinsic porous nature of lightweight expanded perlite absorbs sound waves and reduces the reverberation time.
Another option is the use of perlite as  filler in spray-on absorbers. During spraying, perlite is mixed with a binding agent and water to produce a soft lightweight material with a coarse surface texture and high sound absorption characteristics.
In one application, spray-on absorber containing perlite achieved a NRC value of 0.70.

Sound-Blocking Perlite Products –
Expanded perlite is an essential constituent of perlite lightweight concrete. Densities greater than 1,000 kg/m3 (62 lb/ft3) off er a higher degree of sound-blocking.
By varying the amount of perlite used in the mixture, one can achieve a balance between the weight of the overall structure, and the need for sound blocking levels of sound insulation.
For example, the airborne sound insulation per Approved Document E–UK for new dwellings is 45 DnTw + Ctr dB. By de finition, this is the weighted Sound Reduction Index with the addition of a low frequency sound correction factor (Ctr).
Perlite manufacturers have developed a variety of performance

Most building codes now require  oors, external walls, and intertenancy walls to comply with varying solutions for harnessing the bene ts of perlite lightweight concrete to meet the stringent local building code requirements.
For example:

Perlite Lightweight Concrete Floor Sound-Blocking Solutions –
Perlite lightweight concrete  oor screed is used to reduce unwanted sound transfer between fl oors in a multilevel building.  A typical perlite lightweight concrete  oor installation with an oven dry density of 1,300 kg/m³, at a thickness of 50 mm (2 in.) applied directly (bonded) on 200 mm (8 in.)
thick reinforced cement concrete (RCC) slab achieves an airborne sound rating of: Rw (C; Ctr) = 56,1 (-2 ;-6) dB. 

Perlite Lightweight Concrete In-Fill Partition Wall Systems –
A sustainable drywall partition developed using perlite lightweight concrete in-fi ll at a density of 1,000 kg/m³ gives this partition wall system a minimum 4-hour  fire rating and complies to 45 DnTw +
Ctr dB for intertenancy walls (Figure 3).  is is achieved with a thickness of 200mm (8 in.)
illustrates the sound performance index of the perlitebased partition system with varying thicknesses.

Further Bene ts of Perlite When Used as a Filler in Construction Applications:
Excellent thermal insulation
Lightweight
Safe to handle; non-toxic, inert and inorganic material
Fireproof and non-combustible
Resistance from corrosion from most chemicals
Cost e ective
Low environmental impact



 

The  Water-Holding Capacity of Perlite
Th e natural size and unique structure of expanded perlite makes an ideal framework to hold water.

Perlite holds water in one of three ways: in between individual grains, in channels leading to the cores of the grains and on the highly irregular surfaces of each particle.
Th e surface of perlite is made up of the outer convex shells of glass bubbles and concave openings, so each particle can soak up a good amount of water.
While perlite can hold a variety of liquids, many of the actual applications involve water, so it is used here to illustrate and simplify this process.

Gradation Aff ects Capacity
Th e amount of water taken up by particles of perlite is largely dependent on particle sizes. Just as fi ne, clay-rich soil holds more moisture than coarse, sandy soil, diff erent particle size distributions of expanded perlite hold more moisture than others

Moisture Retention and Release
Some applications need water or other liquids to remain in the perlite, while other applications bene t from the release or drainage that perlite provides. 
The perlite industry provides both coarse grades that drain liquid easily, and fi ne grades with lower porosity that retain more water for longer periods of time.

There is a method used by the greenhouse and nursery industry to visualize moisture retention and release in growing media.
In this method, growing media is saturated with water and allowed to drain by gravity alone to determine its maximum water-holding capacity. 
Then, small increments of pressure are added to simulate the eff ect of suction of moisture and nutrients caused by plant roots in soil.
Th e resulting curves in the chart demonstrate how di erent sizes of perlite grains respond di fferently to increasing amounts of pressure.
Th e maximum water-holding capacity for various grades of perlite at gravity pressure are summarized.
Professional growers in di fferent regions take advantage of these diff erences to achieve optimal moisture levels for their climate.
A dry environment requires more water retention, while a cool and damp environment would demand a grade with higher drainage rates. 
Through the years, the industry has gathered information on the needs of these growers and provides them with the best particle size distribution and density materials.

Wicking Ability and Drainage Rate
Two more factors aff ecting perlite’s water-holding capacity are its miraculous ability to soak up moisture against the opposing force of gravity, and secondly, its ability to let excess moisture drain out to just the right level for plant roots.
Water mobility in perlite is excellent regardless of initial moisture levels due to relatively fast-acting capillary action. 

Water-holding Applications
Many applications take advantage of perlite’s moistureholding capacity. Among the most successful are:
• Soilless growing media
• Seed starting
• Plant propagation
• Hydroponic growing
• Vegetated roofs
• Stormwater bio ltration
• Turf underlayment
• Native soil amendment

 

Th e Water-Holding Capacity of Perlite

In the arid Middle East, perlite has been used with success as an absorbent layer between the root zone and desert sand.
Reports are that less than 50% of the normal water usage is needed to maintain the quality of sod and other plantings.
In a separate example, farmers in the United States have begun adding perlite to their  elds to improve workability, air and water-holding capacity to their soil.
Perlite helps combat compaction in native soils and helps increase the level of healthy biological activity by increasing oxygen in the root zone.

As a general rule, clay-rich soils need coarser grade perlite to provide good drainage while medium grade perlite off ers a balance between air and water-holding capacity.
Fine grades will help with moisture retention in fast draining sandy soils. 

Perlite, Water Conservation & Sustainability
Perlite has an important role to play in conserving the world’s fresh-water resources.
Intensive greenhouse and container growing, produces greater yields per acre, and is o en a more ecient use of water than  field growing.
Even in very arid regions, perlite can be used as a growing medium to feed the local population using limited resources

As opposed to other growing media, perlite readily gives up its water to plants, meaning plants expend less energy extracting water from growth substrates, and put more energy into root and vegetative development.
And since perlite is derived from natural sources, growing media containing perlite can be composted or recycled a fter use and won’t add to the global landfi ll crisis.
Th ere are endless possibilities of how this versatile mineral can be used to store and release water, nutrients and other liquids


 

Solutions to Weighty Problems
The current, eco-friendly trend of designing commercial buildings with rooftop gardens has put a premium on the use of expanded, volcanic perlite in making lightweight soils for these structures. Regular, wetted soil can tip the scales at well over 100 pounds a cubic foot — while a perlite/peat moss mixture will weigh a mere 40 pounds while providing the long acknowledged advantages of superior air porosity and water-holding capacity for plants.
Rising fuel costs have also forced nurserymen to acknowledge the lightweight advantages ofperlite-based soil mixes when shipping plants across the country. All signs are for continued growth in this valuable industrial mineral.

The System
Horticultural perlite and peat moss mixtures are used by professional growers for many reasons. They form a lightweight planting mix for rooftop gardens and other areas where normal soil use presents a weight problem.
Advantages
• Lightweight—Horticultural perlite and peat moss, fully watered, weigh only 40 lbs. per cubic foot. Soil fully watered weighs 100 to 125 lbs. You can reduce planter weight by at least 60% by specifying horticultural perlite and peat moss as a growing mix.
• Long-Lasting Economy—Horticultural perlite is an expanded volcanic mineral.
Unlike organic matter, perlite will not deteriorate.

• Retains Water and Plant Food—Horticultural perlite will retain three to four times its weight in water and will not become soggy.
At the same time, it increases the nutrient and air-holding capacity of the planting mix.
• Chemically Inert—Horticultural perlite has an essentially neutral pH and will not noticeably change the alkalinity or acidity of a planting mix.
The planters themselves can be constructed of reinforced concrete.
To further reduce weight, use of perlite aggregate concrete will reduce planter weight at least 75%.
Pre-formed fiberglass planters may also be used to save weight. Recommended planter depths are indicated in diagram at bottom of sheet.
Rooftop Garden on the Marriott Hotel Parking Garage

Application
Suggested mix for nurserymen who prefer some soil in their planter mix, the following proportions have been suggested for one cubic yard:
• 1/3 cubic yard horticultural perlite
• 1/3 cubic yard coarse peat moss
 
 

Perlite Solutions for the Green Building Industry
Perlite is a natural fit for green building initiatives and certifications

Green building solutions are increasingly called for to balance the world’s need for more human habitation with limited resources.
It is said that buildings in the United States use one-third of the total energy consumed, two-thirds of the electricity, one-eighth of the water, as well as impacting the land.
Green building initiatives consider a building’s energy use, water use, indoor environmental quality, and the materials used in its construction.
In addition, it assesses the eff ects a building has on its site and uses this information to further sustainable solutions throughout the entire life cycle of a building.
Perlite’s versatility and usefulness have an essential role to play in contributing to di erent types of green building initiatives.
Multiple Attribute ratings programs such as LEED (USGBC) and new building standards such as the National Green Building Standard (IgCC), encourage the use of materials and practices that prioritize more energy effi cient systems and environmentally friendly materials.

BENEFITS OF PERLITE IN CONSTRUCTIONS AND BUILDINGS:
■ 100% natural; produced without harmful chemicals
■ Will not o -gas
■ Inert and pH balanced
■ Will not leach chemicals into the environment
■ Is an excellent insulator
■ Lightens denser materials like concrete and soil
■ Promotes plant growth; reduces irrigation demand
■ Can often be locally sourced
■ Provides stormwater detention and  ltration
■ Is durable and has long-lasting bene ts
 

Th ermal Performance
Perlite is an excellent insulator and is therefore prized for its contribution to Optimized Energy Effi ciency and  ermal Comfort.
Perlite is applied both as loose fi ll insulation in cavity walls and below floors, and as an alternative to sand in lightweight insulating concrete roof designs.
Further points may be awarded for Low Emitting Materials since perlite is hypo-allergenic and does not off -gas volatile organic compounds.

Water Effi ciency
Another area perlite contributes to LEED certi cation is in Indoor & Outdoor Water Use Reduction.
Horticultural perlite can store trace amounts of irrigation or rainwater for later release and uptake by planting and vegetation



 

Perlite in Lightweight Manufactured Stone
Lightweight, incombustible, and compatible with many other materials, expanded perlite offers significant advantages when used in the making of masonry veneer products.

Decorative, fireproof, lightweight, and insulating manufactured stone can be made with expanded perlite. 

The physical characteristics of expanded perlite lend themselves to a variety of special purposes—including use as a component of lightweight manufactured stone. For a detailed explanation of perlite expansion, see info sheet: Why Perlite Works.
Expanded perlite is widely seen as an economical way to lighten concrete and plaster. But did you know it can also be used to enhance manufactured stone and masonry veneer products?
Manufactured stone (also known as simulated stone) made with perlite, is fire resistant, weighs as little as one third as much as generic versions, and above all—is attractive!   

Advantages of Perlite Manufactured Stone
Perlite manufactured stone products are lightweight thereby reducing strain on workers accustomed to handling denser materials like stone. They are less energy intensive to ship, and offer added insulating benefits resulting from the bubbles of trapped air that constitute expanded perlite.
Perlite can be used in place of materials that are denser, more costly, or harder to come by, or simply to lend alternative textural or visual appeal.
Manufactured stone products are excellent for hiding irregular wall surfaces and may be used in new construction, remodeling and in exterior applications, depending upon the binder used.

Mix Compounds
Perlite concrete and plaster aggregates conforming to ASTM specifications are commonly used in the making of manufactured stone. Binders and other components of perlite manufactured stone usually include Type I or Type III Portland cement, gypsum, lime, clay and castable or other resin