Obsidian

“Nature's volcanic glass”

Igneous

Obsidian is a naturally occurring volcanic glass formed when lava cools so rapidly that crystals don't have time to grow. Its smooth, glassy texture and conchoidal fracture made it one of humanity's earliest tool-making materials, prized for razor-sharp edges.

Composition

silicon dioxide (amorphous)

Where Found

Iceland, Italy, Mexico, Oregon (USA), Japan, Turkey

Mohs Hardness

5-5.5

Fun Fact

Obsidian blades can be sharpened to just 3 nanometers thick — roughly 500 times thinner than a steel surgical scalpel.