mineral

Polished black stone, possibly black jasper or obsidian

Uncertain; candidates include microcrystalline quartz (SiO₂; black jasper) or volcanic glass (obsidian, SiO₂)

AI-generated identification · may be incorrect

Small, smooth, highly polished dark brown-black pebble with a glossy luster and no visible crystals or cleavage. Likely hardness about 5–7 Mohs; density and streak would be needed for reliable identification.

Identified September 22, 2026More mineral →

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At a glance

Common name: Polished black stone, possibly black jasper or obsidian
Scientific name: Uncertain; candidates include microcrystalline quartz (SiO₂; black jasper) or volcanic glass (obsidian, SiO₂)
Category: mineral
Identified: September 22, 2026
Method: Standard

AI Estimated Value

$2–$15 for a small polished common stone; higher only if confirmed as an attractive, unusual variety.

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

If jasper, it formed by silica-rich replacement or sedimentary silicification; if obsidian, it cooled rapidly from felsic lava, generally during the Cenozoic or older volcanic episodes.

Uses & applications

Used as a worry stone, cabochon, ornamental pebble, or jewelry component; common pieces have modest commercial value.

Geological facts

The rounded shape and polish indicate human processing, but it remains a geological specimen under the stated criteria. Black obsidian commonly shows conchoidal fracture, while jasper is opaque and usually slightly granular.

Field identification & locations

Likely identification requires a scratch test, streak test, translucency check, and specific gravity. Comparable materials occur worldwide, especially volcanic regions for obsidian and silica-rich volcanic or sedimentary terrains for jasper.