contains a high percentage of silica, up to 70 percent. Magnesia can trap gas bubbles in the magma chamber of volcanoes because it is viscous and thick. Different minerals crystallize at different ...

That’s because obsidian is pretty unstable as far as rocks go; over time, the silica molecules within it end up rearranging into a more organized fashion, a process known as devitrification.

Respirable crystalline silica – very small particles at least 100 times smaller than ordinary sand you might find on beaches and playgrounds – is created when cutting, sawing, grinding, drilling, and ...

Crystalline silica is created when cutting, sawing, grinding, drilling and crushing stone, rock, concrete, brick, block and morter. There are many types of activities that produce crystalline silica ...