A black or dark grey, brittle, volcanic glass-like rock which was an important material for tool production in those parts of the world – such as the Greek Mediterranean – where it occurred naturally
Natural volcanic glass Colour ranges from nearly translucent through black, red and green The best raw material for the manufacture of flaked stone tools
A volcanic glass (also called Apache tears) that is usually black, but occasionally red, brown, grey, green (rare), dark with "snowflakes," or even clear This glassy, lustrous mineral is found in lava flows, and obsidian stones can be massive Obsidian is formed when viscous lava from volcanoes cools rapidly Most obsidian is 70 percent silica
{i} black transparent volcanic rock that is formed from the cooling process of molten lava
dark green or black glass formed by volcanic activity; often used for jewelry, amulets, or for the eyes of statues
Natural glass of volcanic origin that is formed by the rapid cooling of viscous lava. It has a glassy lustre and is slightly harder than window glass. It is typically jet black, but the presence of hematite (iron oxide) produces red and brown varieties, and tiny gas bubbles may create a golden sheen. It is sometimes used as a semiprecious stone. Obsidian was used by American Indians and others for weapons, implements, tools, and ornaments, and by the ancient Aztecs and Greeks for mirrors