mineral

Possible tektite or volcanic glass specimen

Natural silica glass; composition commonly near SiO₂, but exact identification requires chemical testing

AI-generated identification · may be incorrect

Black to dark brown, vitreous-to-resinous luster, strongly convoluted or fluted surface, and no visible crystal structure; hardness is typically about 5–6 Mohs. The elongated shape and glossy, flow-like texture may also resemble industrial slag, so visual identification is uncertain.

Identified August 10, 2026More mineral →

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At a glance

Common name: Possible tektite or volcanic glass specimen
Scientific name: Natural silica glass; composition commonly near SiO₂, but exact identification requires chemical testing
Category: mineral
Identified: August 10, 2026
Method: Standard

AI Estimated Value

About $5–$50 for common volcanic glass or slag-like pieces; approximately $20–$200+ for verified, attractive tektites, depending on provenance and rarity.

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 genuine, it may be a tektite formed by meteorite-impact melting, or volcanic glass such as obsidian formed by rapid cooling of silica-rich lava; age depends on locality. The pictured surface could alternatively be weathered anthropogenic slag.

Uses & applications

Tektites and obsidian are mainly collector specimens; obsidian is used for ornaments, tools, and occasionally jewelry. Slag has little geological or commercial value.

Geological facts

Tektites commonly show aerodynamic forms and sculpted ablation surfaces, while obsidian usually has conchoidal fracture and a more uniformly glassy texture.

Field identification & locations

Check for conchoidal fracture, low density, bubbles, magnetic response, and a fresh unweathered surface; laboratory XRF, specific gravity, and microscopy are needed to distinguish tektite, obsidian, and slag. Common tektite localities include Southeast Asia, Australia, and North America.