|K2O Content (%)||5-6|
|Temperature ranging||–273 0 C to +1000 0 C.|
Expanded perlite is formed when normal pyrite is heated. As it heated, the water that’s trapped in the volcanic glass vaporizes and tries to escape. This causes the perlite glass to expand to 7-16 times its original volume, and remaining trapped air changes the color from dark to a brilliant white.