Obsidian

Obsidian rocks are igneous rocks that form when lava cools quickly above ground. Obsidian is actually glass not a mixture of minerals. Often the lava pours into a lake or ocean and its cooled quickly. This process produces a glassy texture in the resulting rock. Iron and magnesium give the obsidian a dark green to black color, obsidian has been used by ancient people as a cutting tool, for weapons, and for ceremonial purposes and is sometimes found by archaeologists in excavations.

Five interesting Facts: 1. often confused with smoky quartz, obsidian has similar properties to quartz because of a similar chemistry 2. Obsidian is a natural occurring glass formed as an extrusive igneous rock. 3. Obsidian has a relative its named (Rhyolite) 4. the thickness of hydration tells the age of the obsidian rock. 5. Conchoidal fracture shows why obsidian was valued by the native people for making arrowheads and tools.

Color- Is dark green to dark brown and black also can show sheens of gold or green, yellow, and/or purple coloration. Sometimes with white inclusions (Snowflake Obsidian)

Where forms: It is found in volcanic lava when it comes into contact with water often it pours into a lake or ocean and cools quickly. This process makes a glassy texture.

Uses of Obsidian rock: 1. Used as a semiprecious stone 2. Ornamental stone for carvings 3. Like flint it could be used for arrowheads and other tools. 4. Polished to create early mirrors 5. Decorated artifacts