Product         photo
 
 
 

Obsidian
Obsidian is a kind of volcanic rock. Its main composition is SiO2 and it is a kind of natural glass formed by rapidly cooled volcanic lava. It is mainly used in handicraft, gem, building materials, refractory material and so on. Under high temperature, it can expand by over 20 times. The color is milky white, and is used in building industry.