mineral

Polished black stone, possibly obsidian or black jasper

Indeterminate; likely volcanic glass (obsidian, SiO₂) or microcrystalline quartz (jasper, SiO₂)

AI-generated identification · may be incorrect

Small, rounded, highly polished dark specimen with a black surface and a brown-gold inclusion or patch. Obsidian has Mohs hardness ~5–5.5, glassy luster and conchoidal fracture; jasper is ~6.5–7, opaque, and usually dull to waxy.

Identified September 12, 2026More mineral →

Explore Polished black stone, possibly obsidian or black jasper in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Polished black stone, possibly obsidian or black jasper
Scientific name: Indeterminate; likely volcanic glass (obsidian, SiO₂) or microcrystalline quartz (jasper, SiO₂)
Category: mineral
Identified: September 12, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a small polished common specimen; higher only if the inclusion, locality, or workmanship is distinctive.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Obsidian forms when silica-rich lava cools rapidly, generally during the Quaternary and younger volcanic activity; jasper forms when silica-rich fluids replace or cement sediments. The image alone cannot establish which material is present.

Uses & applications

Used as a decorative stone, cabochon, bead, carving material, or collectible; obsidian also has historical tool-making significance.

Geological facts

Obsidian is volcanic glass rather than a crystalline mineral, while jasper is cryptocrystalline quartz. The golden area could be iron staining, another mineral inclusion, or reflected light.

Field identification & locations

Check fracture: sharp conchoidal edges and glassy translucence favor obsidian; granular texture, stronger scratch resistance, and opaque waxy appearance favor jasper. Common sources include Mexico, the western United States, and volcanic regions worldwide.