What is Volcanic glass used to make sharp edged knives?

Volcanic glass, primarily obsidian, is used to make sharp-edged knives due to its ability to fracture conchoidally, producing very sharp edges. This natural glass can achieve an edge that is sharper than some steel blades, making it effective for cutting and slicing. Additionally, its lightweight and aesthetic qualities make it a popular choice for both functional tools and decorative items. Obsidian knives are often used in surgical applications and by enthusiasts in traditional crafting.