Obsidian

Obsidian from Mexico Size- 3.6cm x 3.6cm x 2.7cm Weight- 34g You will receive the item in the photo Obsidian is a naturally occurring volcanic glass rather than a mineral. Because of this,it has no crystal system and an amorphous (random) internal structure. Mineral class: obsidian is not a mineral it is technically classified as a mineraloid. It is composed primarily of silicon dioxide along with variable trace impurities (like iron and magnesium) that give it colour. Rock formation: Obsidian forms as an extrusive igneous rocks. It is created when silica rich felsic lava extrudes from a volcano and cools so rapidly that atoms cannot arrange themselves into a structure,crystalline pattern. Hardness: measures between 5.0-5.5 on the MOHs scale. When broken it fractures in smooth curved surfaces which creates the sharpest natural edges known.