VERMICULITE is a hydrous, silicate mineral that is classified as a phyllosilicate and that expands when heated. Vermiculite is darker in color than Perlite and resembles mica.
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. Perlite is white and puffy like popcorn.
The main difference between both minerals is the fact that Vermiculite absorbs and holds water while Perlite does not absorb water.
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So where do you find Vermiculite or Perlite in your area?
If your local LANDSCAPE AND MASONRY SUPPLY doesn’t carry 2cf or 4cf bags of Vermiculite or Perlite, you can also try your local plant nursery as both minerals are used in potting soil to help retain moisture (it’s those little white balls in the potting soil).
If that’s a no-go, simply jump over to the Uline.com and purchase (2) of the 4cf bags of GRADE 2 or GRADE 3 Vermiculite. They will ship the Vermiculite to your home or jobsite. Their Vermiculite is always in stock and their prices are decent.
DO NOT go to your local Big Box hardware store or Plant Nursery and buy bag after bag of the small 8qt or 10 Liter bags of Vermiculite or Perlite. You would need over 200 of the 8qt bags to equal the 8cf bags of Vermiculite / Perlite that is needed for the construction of your BrickWood Box. If you see the words “Quart” or “Liter” on the bag (like the example shown on the right) – put it back on the shelf and look for 2 cubic foot or 4 cubic bags.