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 ...

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 ...

For the ancestral peoples of the Pacific Coast, obsidian (volcanic glass) was a highly valued raw material because it could be used to make razor-sharp cutting tools. However, for many parts of the ...