all depends on what sample you have
Obsidian is 3 in deep
Obsidian is not identified, classified, or described by height. It is described by its texture, fracture, hardness, and chemical composition.
The size of an average sized head
Actually, obsidian doesn't have grains at all. Technically obsidian is a glass, which means it has no internal structure. When geologists refer the the grain size of a rock, they mean how big the crystals that make it up are. Since obsidian has no crystals, it therefore has no grain size.
Obsidian is a naturally occurring volcanic form of glass.
Obsidian
Trade. Obsidian was one of the things that played a big role in trade.
Trade. Obsidian was one of the things that played a big role in trade.
Mahogany Obsidian
No. Obsidian is brittle.
No. Obsidian is natural glass, mostly silica. Obsidian is of volcanic origin.
Obsidian is, itself, a mineral.