Description

General Description: Vermiculite {(Mg, Fe, Al)3(Al, Si)4O*0(OH)2 - 4H2O, Hydrated Magnesium Iron Aluminum Silicate Hydroxide} is an important member of the Montmorillonite/Smectite Group, members of which also belong to the larger general group known as the Clays. Vermiculite is also sometimes placed in the Mica Group, although recent analysis has excluded it from this group. Vermiculite is basically overly hydrated biotite or phlogopite. Natural specimens originated as these minerals and later altered to vermiculite through weathering or hydrothermal processes. Vermiculite typically forms small platy mica like crystals. These crystals contain water in their structures and when heated to above **0C, the water turns into steam causing the crystals to expand rapidly. The volume increase can be ***0 to even ***0%. Appearance: Flakes or powder Origin: China Applications Vermiculite is very useful for many industrial purposes. It is very lightweight, chemically non-reactive, fire resistant and odorless. Vermiculite can be used to soak up such toxic liquids as fertilizers, herbicides and insecticides. It is this ability that is also being put to good use as a bedding for pets and livestock. In addition, vermiculite can be used in concrete and ceramics as a heat resistant additive. Important Properties Vermiculite is usually brown to golden brown, also white, colorless or yellow. Luster is pearly to greasy. Its Crystals are translucent and Crystal System is monoclinic; 2/m. Its Crystal Habits include pseudohexagonal tabular crystals or "books", also found in compact or lamellar masses or microscopic crystals. The Cleavage is perfect in one direction, basal. Fracture is uneven to lamellar. The Hardness is 1.5 (can sometimes leave marks on paper). The Specific Gravity is 2.3 (below average). Its crystals expand to many times their original volume when heated. Best Field Indicators are softness, color, luster and expandability when heated.