igneous
Black Obsidian
Volcanic Glass (Amorphous SiO2)
AI-generated identification · may be incorrectMohs hardness 5-5.5, deep black color, vitreous luster, amorphous crystal structure with conchoidal fracture, specific gravity around 2.4.
Identified More igneous →
Explore Black Obsidian in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Mohs hardness 5-5.5, deep black color, vitreous luster, amorphous crystal structure with conchoidal fracture, specific gravity around 2.4.
Formation & geological history
Formed as rapidly cooling felsic lava from volcanic eruptions without sufficient time for crystal growth, primarily found in regions with recent volcanic activity.
Uses & applications
Used historically for sharp cutting tools and arrowheads, and commonly utilized today in ornamental carvings, jewelry, and metaphysical collections.
Geological facts
Despite looking like a mineral, obsidian is actually a natural mineraloid glass due to its lack of a true crystalline structure.
Field identification & locations
Easily identified by its dark, glass-like appearance and extremely sharp conchoidal fracture edges; found worldwide near volcanic deposits.
