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Obsidian Stone
Chemical Formula: SiO2
Color: Dark green to dark brown and black
Hardness: 5.0- 5.5
Specific Gravity: 2.6
Obsidian is a hard volcanic glass that displays shiny and curved surfaces. It is formed as a result of volcanic lava coming in contact with water. 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. The stone sometimes may contain small bubbles of air aligned along layers that produce interesting effects such as a golden sheen, known as Sheen Obsidian or a rainbow sheen called Rainbow Obsidian.
Obsidian is often confused with smoky quartz because of a similar chemistry. It has been used by ancient people as a cutting tool, for weapons, and for ceremonial purposes. The stone is found in the regions of Italy; Mexico; Scotland; Arizona, Colorado, Texas, Utah and Idaho, USA.
