What Is The Difference Between Perlite And Vermiculite?

Perlite and vermiculite are both natural materials that have been historically used in  horticultural, industrial, construction and other unique applications. But there is much more to know about each product and how they are commonly used today.

Understanding Perlite and Vermiculite

The key to knowing the differences between perlite and vermiculite is understanding their origins. 

Perlite

It looks like tiny pieces of popcorn, but perlite begins its life as a naturally occurring volcanic glass called obsidian. It draws in water and changes color and texture to become crude perlite. This substrate is then collected, crushed, sorted, expanded using heat, and again sorted (screened) to create a very lightweight material that has a high surface area and resists compaction. Perlite has a white to light-gray coloration.

Vermiculite

Resembling mica in its flat, shiny, and charcoal to brown appearance, it appears in a more worm-like- or accordion-like structure in its expanded form. It is a hydrated magnesium-aluminum-iron silicate material that expands when heated. Vermiculite is a result of the weathering of certain rocks, like phlogopite, due to the effects of water, acidic, or hydrothermal conditions. It is lightweight, highly absorptive, and insulative in nature.

While perlite and vermiculite differ inherently in their makeup, they are admittedly very similar in nature and they can share many similar applications. They are more or less on a sliding scale when it comes to their properties and uses in modern industrial, construction, and horticultural applications. Both substances display excellent fire resistance, insulating, and water retention capabilities. Both perlite and vermiculite are available in an array of sizes for various uses and applications across industries. Always keep in mind that the larger the particle, the more air space; the finer the particle, the more liquid retention. 

Perlite and Vermiculite Applications

Both materials are very lightweight, inorganic (will not decompose), safe, and sterile. They have wide uses in countless industries and applications, including:

Perlite

Horticultural: Perlite is often used for seed germination, rooting cuttings, hydroponic gardening/farming systems, greenhouse growing, and flower bulb storage. It is also part of soilless mixes that are used to grow plants for sale in the nursery trade and can be used as a soil amendment. Coarse grades of Perlite aid in water drainage and prevent compaction, keeping the growing medium loose and allowing for plant roots to access adequate water and oxygen. At the same time, fine perlite can help to retain a significant amount of water without creating a waterlogged substrate. Perlite is non-reactive and has a neutral pH, so it plays well with other components and has a very low CEC (Cation exchange capacity).

Industrial: Perlite is included in various abrasives and is used to absorb hazardous materials. It can also be used as a carrier for substances like pesticides, feed concentrates, and herbicides. Due to its fire-resistant nature, perlite is incorporated into refractory products for fireproofing, insulation, and fillers. Its high surface area makes it ideal for use as a filtration component as well.

Construction: Perlite is lightweight, fire-resistant, and insulative, making it perfect for use in ceiling tiles, chimney linings, and to fill the voids in hollow masonry units and between exterior walls. It’s ideal for fireproofing, insulated/ heated floors, and more. It can be used in various applications, incorporated into gypsum boards, pasters, and stuccos, loose-fill insulation, and used as an aggregate in the production of lightweight/fireproof concrete in pizza and bread ovens, rocket stoves, chimneys, and furnace linings. Perlite’s insulating properties make it ideal for use to reduce sound transmission.

Vermiculite

Horticultural: Vermiculite naturally wicks water and holds onto moisture in a soilless mix, and on its own as a soil amendment. Unique to vermiculite, granules can also hold on to and release key nutrients with a relatively high CEC (Cation exchange capacity), beneficial for growing plants, so it is invaluable when used as part of a soilless mix for growing seedlings and propagating cuttings. It is clean, odorless, non-toxic, sterile, resists molding and deterioration, and pH neutral, making it perfect for use in controlled growing settings like greenhouses and hydroponic systems. Vermiculite is a common inclusion in potting mixes. Due to its absorptive properties, vermiculite can also be used as a carrier for various agricultural chemicals.

Industrial: Vermiculite is fire-resistant and so can be used in fire-resistant boards, coatings, and as a loose-fill insulator. In the production of steel, both perlite and vermiculite can be used to top the molten steel to insulate it and maintain its temperature. They can also work as a slag coagulant and insulator. Certain grades of vermiculite are ideal for use in brake pads, gaskets, and other applications where friction and heat play a role. It can also be used as one of several components that are mixed and used to seal abandoned mines. Vermiculite’s absorptive nature makes it ideal for soaking up spilled liquids and chemicals, and as a cushioning for packaging of hazardous substances. Vermiculite (and perlite) can be used in oil and gas well drilling and other borehole applications. 

Construction: Its lightweight quality makes vermiculite perfect for use in lightweight concrete, building boards, plasters and stucco, roof and floor screeds, and as a filler in chimney linings and firebricks. Vermiculite can also be used for loose-fill insulation in attics, concrete (CMU) walls, and floors. Often, vermiculite is an ingredient in pool base cements for vinyl liner swimming pools. It is commonly used in fireproof sprays and paints, mastics, and sealants for commercial buildings. Vermiculite helps to reduce sound transmission and is often used in acoustic insulation.

Less traditional, more unique uses for perlite and vermiculite include archeological digs, animal bedding and litter, aquarium filtration, glass enameling, pest deterrent, and much, much more. 

Depending on your industry or business, perlite and/or vermiculite could be the solution to a common problem that you are experiencing. Contact Perlite Vermiculite Packaging Industries, Inc. to learn more about the wide and varied uses of perlite and vermiculite and see how they can benefit your products and processes.