Vermiculite FAQ

At PVP Industries, Inc., we’re vermiculite manufacturers and we love to talk all things perlite and vermiculite. Our vermiculite and perlite distributors and other clients who purchase our products have plenty of questions, and we’re always ready to answer them. We’ve already touched on some top queries we get about perlite, now it’s time to answer some commonly asked questions about vermiculite. And of course, if you have any additional questions that aren’t listed here, please contact us and we’ll be happy to share what we know.

What is vermiculite and how is it made?

PVP vermiculite is a naturally occurring mineral that resembles mica. It is a hydrated magnesium-aluminum-iron silicate material that forms as a result of the weathering of certain rocks. In its raw state vermiculite is flat, shiny and charcoal to brown in color. After being harvested from open-pit mines, raw vermiculite is super-heated (between 1,472°F and 1,832°F (800°C - 1,000°C)), causing rapid expansion. The resulting worm-like or accordion-like structure is vermiculite’s exfoliated form. This processed vermiculite is then sorted to be best used by the end consumer in a range of available grades.

Where does vermiculite come from?

Vermiculite is found naturally in any place where the unique combination of minerals and environmental conditions are right to precipitate formation. There are large vermiculite deposits found across the globe, from the United States to Brazil, Uganda, Turkey, Zimbabwe and South Africa.

What are the properties of vermiculite?

PVP vermiculite is lightweight, highly absorptive, and insulative in nature once it has been heated and expanded. It is also naturally sterile, inert and pH neutral, making it very versatile across industries and uses, from conventional to unique. Vermiculite is also fire-resistant and low-density while maintaining dimensional stability.

What are the different grades of vermiculite?

After vermiculite is expanded and separated, it is then graded by particle size and separated for use in various applications. Available grades of PVP vermiculite include:

• Super Coarse (A4)
• Coarse (A3)
• Medium (D3, A2.5)
• Fine (A2)
• Micron (A0)

What is the difference between perlite and vermiculite?

PVP perlite and PVP vermiculite are both natural, mineral-based materials. Perlite is derived from volcanic glass called obsidian and vermiculite results from the weathering of certain rocks. After processing, perlite and vermiculite are very different in appearance–perlite is white and puffed and vermiculite is flat, shiny and brownish-gray. While they differ in their makeup, they are very similar in nature and share many similar properties and applications. They are both available in a range of grades for any number of needs and use cases.

What is vermiculite used for?

PVP vermiculite has a wide range of uses and applications across industries–horticultural, industrial and construction–from typical to unique. In the horticultural world, vermiculite is often used to improve soil texture, aeration and water-holding capacity, along with being used to propagate plants and grow seedlings. In the construction and industrial fields, vermiculite is used for its insulative, fire-resistant, absorbent, lightweight and thermal properties. It is often used as part of lightweight concrete mix and in various masonry applications as well as in environmental cleanups and hazardous packaging. Vermiculite also has plenty of agricultural uses in relation to animal care.

Is vermiculite natural or synthetic?

Vermiculite is a 100% natural material. The finished, expanded form differs from how it is found in nature, but it is still a natural product.

Is vermiculite safe to use?

Yes, vermiculite is inert and non-reactive, and also non-toxic–it is very safe to handle and use. In fact it is often used in animal feed as a carrier to dispense medications and nutrients and as animal bedding and reptile egg incubation. The only caution would be to take care and use appropriate PPE and adequate ventilation when handling very fine grades of vermiculite, since the tiny particles can easily be inhaled and cause irritation.

Does vermiculite contain asbestos?

Modern vermiculite does not contain asbestos. Historically, before 1990, vermiculite from a certain area in Montana had been found to be contaminated with naturally occurring asbestos. This has not been an issue for several decades, and you can trust that PVP vermiculite is asbestos-free.

Vermiculite vs perlite – which is better?

Neither is “better”–they both have their best intended uses. There are many applications that could call for both PVP perlite and PVP vermiculite. When should you use vermiculite instead of perlite? In general, when you need an inert, lightweight mineral-based material that offers ideal thermal insulation, fire resistance, moisture retention and sound dampening, consider vermiculite. If you have a specific application in mind and are not sure whether perlite or vermiculite would be best, feel free to contact us. 

Is vermiculite biodegradable?

No, vermiculite is not biodegradable. This is because it is a mineral and so is not made out of organic material that contains carbon and can slowly break down over time. The only way for vermiculite to break into smaller particles is by physical compaction, shattering, or under extreme pressure or aggressive abrasion. Instead, vermiculite is durable, non-toxic, and resists decomposition, which is actually one of its properties that makes it so valuable for insulative, fireproofing, packaging, and soil amendment applications where long-term stability is the goal.

Is vermiculite organic?

There are two main usages of the word “organic.” One use is referring to animals and plants and their byproducts in the sense that they contain carbon–vermiculite is not organic according to this definition. However, “organic” is also used to refer to a way of operating, a set of practices used in farming and agriculture. By this definition, PVP vermiculite is organic, as it is non-toxic and naturally occurring and has been approved for use in organic applications. 

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

We have articles on our website that address typical uses for various grades of PVP perlite and PVP vermiculite, however if you have a very specific use case and are unsure of which of our grades may best suit your application, please contact us to discuss.