Obsidian Blade

Volcanic glass sharper than a steel scalpel/Geology & Minerals

Obsidian is a naturally occurring volcanic glass formed when felsic lava cools rapidly. Obsidian blades knapped by skilled artisans can have edges just a few nanometers thick, making them sharper than the finest surgical steel. Mesoamerican civilizations, particularly the Aztecs, used obsidian for weapons, tools, and mirrors. Some modern surgeons use obsidian scalpels for delicate procedures because they cause less tissue damage than steel.