Tag Archives: Volcanic glass

Obsidian


Obsidian

Obsidian is a very shiny volcanic glass that is sometimes used as a semiprecious stone. Though it is formed by the rapid cooling of viscous lava, obsidian is only slightly harder than window glass. It is typically jet black, but the presence of hematite produces red and brown varieties, and tiny gas bubbles may create a golden sheen. Obsidian was used by Native Americans for weapons, implements, tools, and ornaments and by the ancient Aztecs and Greeks for mirrors. What is snowflake obsidian? More… Discuss