igneous
Polished black stone bead, possibly black obsidian
Likely obsidian (natural volcanic glass; composition chiefly silica-rich volcanic glass), but identification is uncertain from the image
AI-generated identification · may be incorrectSmall, elongated, glossy black bead with a smooth polished surface. If obsidian, hardness is about 5–5.5 Mohs and it has no crystal structure or cleavage; the bead’s material cannot be confirmed visually.
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Physical properties
Small, elongated, glossy black bead with a smooth polished surface. If obsidian, hardness is about 5–5.5 Mohs and it has no crystal structure or cleavage; the bead’s material cannot be confirmed visually.
Formation & geological history
Obsidian forms when silica-rich lava cools rapidly, commonly in volcanic settings; its age depends on the source deposit. The bead has been shaped and polished by people.
Uses & applications
Beads are used in jewelry and craftwork; obsidian is also collected and has historically been used for sharp tools.
Geological facts
A glassy luster and black color fit obsidian, but several other stones and manufactured materials can look similar.
Field identification & locations
A visual check alone cannot distinguish obsidian from onyx, other black stones, or glass. A scratch or fracture test may damage the bead, so use professional gemological testing for confirmation.
