Crude Vermiculite

In magneziate-iron micas have a group of hydromicas containing ceolite water. These include micas, vermiculite, similar in chemical composition of hydrated biotite and phlogopite, minerals from which as a result of exchange reactions occurred glauconite, corresponding to the composition of hydrated lepidomelanu.

Vermiculite (from the Latin. Vermiculus - worm), a natural mineral from the group hydromicas having a layered structure. The product of secondary changes (hydrolysis and subsequent weathering) of dark micas biotite and phlogopite, is characterized by variable amounts of Fe, Mg and Al; there may be significant traces of Ca, Mn, and slightly Ti, as well as traces of Na, K, F, Ni, Cr and Ba. Color bronze tan to dark to bright pearl luster. In industry to vermiculite are also intermediate varieties between biotite and vermiculite (gidrobiotit), phlogopite and vermiculite (gidroflogopit).

The chemical composition corresponds to the approximate formula:

(Mg+2, Fe+2, Fe+3)3 [(AlSi)4O10]·(OH)2·4H2O

  • hardness mineralogical scale 1-1,5;
  • density 2,4-2,7 g/cm,3 (swollen - 0,065-0,130 g/cm3;
  • melting point 1350 °C;
  • not susceptible to abrasion and lubricating properties similar to graphite;
  • when heated to a temperature of 900-1000 ° C bubbled and increases in the amount of 15-25 times;