mineral

Green glassy slag (often sold as “sea glass” or “green obsidian”)

Industrial vitreous slag; primarily amorphous silicate glass, composition variable

AI-generated identification · may be incorrect

Usually translucent emerald to bottle-green, with vitreous luster, conchoidal fracture, no crystal structure, and hardness roughly 5–6 Mohs. Rounded surfaces and bubbles strongly suggest tumbled or weathered glass/slag rather than natural obsidian.

Identified September 22, 2026More mineral →

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At a glance

Common name: Green glassy slag (often sold as “sea glass” or “green obsidian”)
Scientific name: Industrial vitreous slag; primarily amorphous silicate glass, composition variable
Category: mineral
Identified: September 22, 2026
Method: Standard

AI Estimated Value

About $1–$5 per piece or $5–$30 for a small lot; unusually clear, attractive polished pieces may sell for $10–$50.

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

Formed by rapid cooling of molten industrial material, commonly iron- or copper-processing slag; it is human-made and typically geologically recent, not an igneous rock. The pieces appear polished or naturally rounded, possibly in a rock tumbler.

Uses & applications

Used decoratively in landscaping, crafts, specimen displays, and jewelry; generally unsuitable for structural construction. It has modest lapidary appeal when transparent and bubble-free.

Geological facts

The bright green color commonly comes from iron, chromium, or copper-bearing glass chemistry. Natural obsidian can be green but is usually more uniformly glassy and lacks abundant rounded, vesicular forms.

Field identification & locations

Identify by abundant internal bubbles, irregular melted shapes, uniform glassy fracture, and lack of mineral grains or cleavage; a glass-scratch test and microscope examination can help. Common around historical smelters, foundries, dumps, and tumbled-glass markets.