Obsidian arrowhead
You will be picked one out at random
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.
