Black Obsidian

Obsidian is an igneous rock, a mix of cryptocrystalline grains of silica minerals in a glass-like suspension. It is a natural occurrence of volcanic glass created when lava from a volcano cools rapidly with minimal crystal growth. 

Since Obsidian is a natural glass, if in it's raw, unpolished form, it may have razor-sharp edges that can easily cut skin and flesh if broken. Handle with care. Do not grind dry since long-term exposure to finely ground powder may lead to silicosis.

Crystal System: Amorphous Crystal System
Chemical Composition: SiO2_Silicon_Dioxide_with_impurities
Hardness: 5 to 5.5 
Color: Black, Black with white inclusions, Brown, Maroon, Green
Origins: China, India, Mexico, United States
Rarity: Common
Pronunciation: uhb-SID-ee-uhn / ob-SID-ee-uhn
Mineral Class: Mineraloids