Vermiculite is a layered structure of magnesium aluminum silicate water secondary metamorphic minerals, like mica ore outside, usually black (K) mica by hydrothermal alteration or weathering from, because heat dehydration deflection when the expansion was like, shape resembles 
 Leech, it said vermiculite. 
 Vermiculite was strong, and scales flake or false monoclinic crystals, scales overlap, within the 0.54cm thick stack of one million; 
 Color was golden, brown, brown green, dark green, black and variegated; density 2.2-2.8g/cm3, hardness 1-1.5, bulk density 
 1.1-1.2g/cm3, melting point of 1320-1350 ℃, compressive strength 100-150MPa. 
 Vermiculite, calcined at 800-1000 ℃, the volume can be rapidly increased 8-15 times, up to 30 times. Into gold or silver color, produces a loose texture of the expanded vermiculite. Vermiculite with heat insulation, cold frost and good sound insulation performance, capacity 90-145kg/m3, the thermal conductivity of 0.047-0.081W / (mK), refractoriness 1300-1350 ℃, the sound frequency of 512Hz when the suction Sound coefficient 0.53-0.63, 95% relative humidity in the environment of -100%, after 24h of 1.1% moisture, soaked in water for 1h, the quality is 265% water absorption, volume absorption was 40.6%. roasting point of 1370 -1400 ℃, tasteless, non-toxic, non-rot, anti-bacterial, but not acid, dielectric properties are poor. Heat capacity / J. (kg.K) -1 0.157