Snowflake obsidian is a form of volcanic glass ... It appears as a dark glassy rock that’s typically black, although it can take on hues of green, brown, and other colors due to impurities.

Archaeologists have evidence for long-distance trade routes across North America that could totally rewrite previously ...

Hand-carved arrowheads and jagged spears made of obsidian, a sharp rock formed by volcanic magma, are remnants of vast ...