Since it's born out of molten rock, obsidian is only found in volcanic regions of the world, including in parts of the United States, such as the Mountain West, Southwest, California, Oregon ...

As with other forms of obsidian, rainbow obsidian is both rock and glass ... which has a long history of volcanic activity. There are four mines in this region that, with a permit, allow the ...

A decade earlier, Rademaker’s advisor, archaeologist Daniel Sandweiss, had made the unexpected discovery of flakes and tools made of obsidian, a volcanic rock, in excavations at one of the oldest ...

Obsidian, formed by the rapid cooling of volcanic magma, is ideally suited for this second ... This is because they have some larger crystals in the rock that makes the obsidian fracture less ...

The obsidian-like “organic glass” formed in ... first deadly event to rip through the town before it was buried by volcanic debris. The black brain fragments are the only documented example ...