mineral

Likely polished/tumbled dark mineral or glassy rock fragment

Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian

AI-generated identification · may be incorrect

Elongate, dark brown-black, strongly glossy specimen with apparent irregular or conchoidal surfaces; hardness likely about 5–7 Mohs, but cleavage, crystal structure, and specific gravity cannot be confirmed visually.

Identified August 27, 2026More mineral →

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At a glance

Common name: Likely polished/tumbled dark mineral or glassy rock fragment
Scientific name: Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian
Category: mineral
Identified: August 27, 2026
Method: Standard

AI Estimated Value

About $1–$15 for a common unidentified polished fragment; attractive, confirmed tourmaline or another collectible mineral might be worth $20–$100+.

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

Could represent a naturally crystallized silicate mineral, such as hornblende or tourmaline, or a volcanic glass fragment such as obsidian; age and formation environment require testing and locality information.

Uses & applications

Small polished specimens are mainly used for collecting, display, and occasionally jewelry; industrial or construction value would be negligible at this size.

Geological facts

The bright streaks and elongated shape may reflect polishing or crystal faces, but lighting and scale make identification uncertain; a streak test, hardness test, and close examination of ends are useful.

Field identification & locations

Check whether it scratches glass, leaves a streak on unglazed porcelain, shows cleavage, or has bubbles/flow texture; common possibilities occur worldwide in igneous and metamorphic rocks.