Perlite FAQ

As perlite manufacturers we know that perlite distributors and other clients who purchase PVP perlite have plenty of questions about our products. We are here to help, with answers to some of the most common questions we receive. If you have any additional questions that aren’t listed here, please contact us and we’ll be happy to shed some light on your query.

What is perlite and how is it made?

People have all sorts of assumptions about what perlite is, but the truth is simple–perlite is a pure, naturally occurring volcanic glass that attracts anywhere from 2-5% water content from the surrounding environment. After it is harvested it’s heated to extremely high temperatures (1600 ℉ / 871 ℃) and the trapped water vaporizes, leading to rapid expansion. The process is much like how a corn kernel expands when making popcorn. Now let’s answer another common question: What is perlite made of?

What is perlite made from?

Perlite is composed of an igneous rock called obsidian–a black-colored extrusive igneous rock that was formed after magma erupted from a volcano. Obsidian forms very close to the Earth’s surface and so cools very quickly, preventing crystal formation. Instead, it is more glass-like. Over time, obsidian draws in water, changing from a dark, glassy substance to crude perlite, which is naturally gray or glossy black. It gains its white color when it is superheated–water vapor is released and the perlite expands. 

How is perlite harvested?

Obsidian–and thus perlite–is found anywhere in the world that has historically seen volcanic activity. It is harvested from volcanic hotspots through open-pit surface mining. Because obsidian and the resulting perlite form relatively close to the Earth’s surface, a large pit is dug to extract the mineral deposits. Specialized machinery rips through the deposit and blasting can also be done if the structure of the deposit isn’t ideal. The crude perlite is then extracted from the ground, crushed, screened, sized, and loaded for transport to expansion plants.

Is perlite natural or synthetic?

PVP perlite is a 100% natural mineral product. It does take some processing and work on the part of perlite manufacturers to make it usable and readily available, but the product itself is first made by nature.

What is PVP perlite used for?

PVP perlite is used across industries and occupations and is often a key ingredient in operations in the construction, horticultural, industrial and other unique sectors. Uses often vary by the many available grades.

What are the properties of perlite?

Perlite is inert, meaning that it exerts no impact or effect and will not interact with other materials. Perlite is also odorless, colorless, non-toxic, and has a neutral pH. It is lightweight, sterile, porous, has excellent thermal/acoustic insulation, is fireproof and highly moisture retentive.

Is perlite environmentally friendly and sustainable?

Perlite is used in the protection of resources and the environment by filtering water runoff and aiding in hazardous waste spills, preventing further contamination. It can also be used as a substitute for native soil, preventing topsoil depletion. It requires no chemical inputs in the production process and produces little to no waste products. So yes, perlite, while being a harvested natural product, is considered to be environmentally friendly and sustainable. Perlite manufacturers are careful to thoroughly evaluate a site for local risks prior to establishing a perlite mine.

What are the different grades of perlite?

At the initial harvest, raw perlite is crushed and screened and separated into a range of sizes. Then, during the heating process, it can break apart into even more particle sizes. Perlite manufacturers use factors like initial particle size, heat intensity, preheat level, air flow, and furnace time to create a full range of sizes, including: Super Coarse, Coarse, Medium, Fine, Super Fine, Insulation Grade, Concrete Aggregate, Industrial Straight Coarse, Industrial Medium, Industrial Medium for Insulation, Industrial Fine and Industrial Super Fine. For perlite distributors or commercial clients, custom perlite mixes are available upon request.

Perlite vs vermiculite – what is the difference?

Perlite and vermiculite are both natural, mineral-based materials that can be used in similar horticultural, industrial, construction and other unique applications. They differ in their origins though, with perlite being derived from volcanic glass called obsidian and vermiculite resulting from the weathering of certain rocks. Perlite is white and puffed, while vermiculite is flat, shiny and brownish-gray. Perlite and vermiculite differ in their makeup and appearance but they are fairly similar in nature, come in a range of grades, and share many similar applications. 

What industries use perlite?

PVP perlite is used across a wide range of industries and sectors, but is especially useful in the following industries: 

• Construction and Building Materials: perlite is used as a lightweight aggregate, for loose-fill insulation, as a fireproofing material, as an additive in lightweight concrete/plaster, and in acoustic ceiling tiles

• Horticulture, Agriculture, and Landscaping: perlite is widely used as a soil amendment to provide aeration and water retention in soilless potting mixes, hydroponics setups, and greenhouse growing; it is also used to reduce soil compaction and improve drainage on grass turf; perlite also acts as a bedding material for poultry and cattle, a delivery method for nutrients and medication, and an anti-caking agent in feed

• Industrial Filtration: perlite can filter and clarify liquids in the Food & Beverage, Pharmaceutical, and Water Treatment industries. It is also used to purify the air in steel mills and in energy production as a scrubber in baghouses and cold boxes.

• Manufacturing and Chemical Industry: perlite is ideal as a lightweight filler in plastics, paints, caulking compounds, and rubber; an abrasive in soaps, cleansers, and polishes; and in refractories to top molten metal and create lightweight bricks

• Cryogenics and Energy: perlite helps to insulate double-walled cryogenic tanks, like those that house liquid natural gas

• Environmental and Safety: perlite is regularly used as part of industrial spill cleanup operations

Does perlite contain asbestos?

No, PVP perlite does not contain asbestos. Because it derives from volcanic glass, perlite is not a typical mineral that could potentially form alongside asbestos. As they are not naturally found near each other, perlite does not risk being contaminated with asbestos.

Is perlite safe to use?

Yes, PVP perlite is non-toxic, sterile, and inert and is safe for both humans and animals. That said, the dust from perlite is very fine and can lead to respiratory and eye irritation if not handled properly. It is highly recommended to wear a mask and moisten the perlite before handling. For a full rundown of PVP perlite’s safety, check out our expanded perlite Safety Data Sheet (SDS).

Can perlite be recycled?

While it is time intensive to recycle perlite, it can be done. Because it is physically and chemically stable and does not readily break down, perlite can be recycled in the sense that it can be cleaned and reused in various ways, depending on the industry and original use. 

Is perlite biodegradable?

No, technically speaking, perlite does not biodegrade because it is inorganic, meaning that it does not contain carbon and so cannot decompose, rot, or break down chemically. Perlite is an inert volcanic glass, and while it won’t decompose or biodegrade, it can break apart or crush into smaller pieces due to physical or mechanical means.

Is perlite organic?

No, perlite is a mineral and is not derived from living matter, so it is not organic in the strictest sense of the word. However, when it comes to the certifying bodies that approve materials for use in organic growing and cultivation, perlite is generally accepted as being approved so long as it is not modified. 

Is perlite the same as Styrofoam?

No! Whether branded or generic, the white synthetic material used to make disposable cups and coolers is a plastic product (extruded polystyrene foam) and is manmade. On the other hand, perlite is a natural, mineral-based material that was heated to expand to its final form.  Perlite has become a widely recognized alternative to Styrofoam, offering a more environmentally responsible and sustainable filler material. Due to its lightweight structure, natural composition, and reduced environmental impact, perlite is increasingly being used in applications where safer and eco-friendly packaging or insulation solutions are preferred.  

How do I determine the right type of PVP perlite for my needs?

We have outlined common uses and unique uses for various grades of perlite and included the key industries that typically make use of perlite, but we realize that your specific niche or use case may not be mentioned. Coarseness and density can vary greatly, and specially formulated custom mixes can also be created upon request. For help to choose the best grade of perlite for your specific application, please contact us.

Are there any storage considerations for perlite?

To best maintain its properties, perlite needs to be stored in a dry location. It readily absorbs moisture, which can compromise the perlite’s efficacy in certain applications. We carefully store our PVP perlite - either in properly configured storage buildings, or when outside, our products are covered and stretch wrapped to protect them from any weathering or other variables that would otherwise compromise the perlite.  You can rest assured that our products are of the highest quality and that we take proper storage seriously.