Obsidian
3 in the gallery
Obsidian is a natural volcanic glass formed when felsic lava erupts and cools rapidly, resulting in a smooth, glassy surface and a characteristic conchoidal fracture. It is typically deep black, sometimes with a subtle brown or greenish tint, and often exhibits a vitreous luster that gives it a sleek, mirror-like appearance. Specimens can show a variety of forms, from irregular nodules to sharp blades and surgical-like conchoidal edges that polish to a near-surgical sheen.
- Rarity
- Common
- Stability
- Stable
- Collector interest
- Moderate Interest
Where Obsidian is found
Top localities
- Hot Springs1 specimen
About Obsidian
Historically, the most well-known sources include volcanic terrains in the United States, with notable material from regions that produced abundant nodular and bladed specimens. Collectors prize fresh, undecorated surfaces that reveal the mineral’s glassy structure, as well as curated samples showing distinctive ripples or banding from rapid cooling. Obsidian’s ease of flaking and the dramatic contrast between a polished, black surface and lighter inner reflections add to its appeal for display pieces and study alike.