A laminar micaceous mineral composed of hydrated magnesium aluminum iron silicate. Vermiculite occurs naturally as a compact ore. It is mined in Russia, Australia, Brazil, South Africa, and the U.S. (Montana, North Carolina, South Carolina, Wyoming, Colorado). When vermiculite is heated to about 300 C (570 F), it expands to form highly porous, worm-shaped curls of connected mica-like plates. Expanded vermiculite is used as a fire-resistant insulator, spill absorbent, and packing material. It is also used as a lightweight filler in Plaster, Concrete, Brick, Rubber, Soil, Paper, Paint, and plastics.
Synonyms and Related Terms
hydrated magnesium aluminum iron silicate; exfoliated hydrobiotite; Zonolite insulation; Microfil; Microlite; Verxite
Vermiculite mined prior to 1990 may contain asbestos which is toxic by ingestion and inhalation.
Noncombustible. Resistant to insects, bacteria, and fungi.
Milllipore Sigma: SDS
Unaffected by water, acids, alkalis or organic solvents.
Can expand 6-20 times when heated. Expanded vermiculite can absorb 200-500% of its weight in liquid.
Fracture = unvevn Crystal system = monoclinic Cleavage = perfect Streak = pale yellow
Resources and Citations
- The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 10095
- Encyclopedia Britannica, http://www.britannica.com Comment: Vermiculite." (Accessed 16 Mar. 2004).
- Wikipedia: http://en.wikipedia.org/wiki/Vermiculite (Accessed Sept. 20, 2005)
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
- Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
- Ceramics and Glass Conservation Section, List of Workshop Materials, The British Museum, London.