Description: This the obsidian specimen, from USA, wide around 6cm, Obsidian is a naturally occurring volcanic glass, mostly contain elements Si, O etc. It was used in antiquity for amulets and necklaces. Many colored glasses are sold as "obsidian" often claiming to be natural. But we can easily determine that this specimen is entirely natural obsidian. Most of the obsidian specimen we seen, were not on the matrix, but this obsidian specimen is rare to on the original matrix. Under the light, inside of the obsidian is gray color, looks more clear. Very rare natural obsidian on the matrix specimen! Professional collectors’ choice!