mineral

Blue slag glass / industrial glass fragment

Artificial silicate glass, composition variable; likely copper- or cobalt-colored furnace slag

AI-generated identification · may be incorrect

Identified September 20, 2026More mineral →

Explore Blue slag glass / industrial glass fragment 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: Blue slag glass / industrial glass fragment
Scientific name: Artificial silicate glass, composition variable; likely copper- or cobalt-colored furnace slag
Category: mineral
Identified: September 20, 2026
Method: Standard

AI Estimated Value

Usually $5–$30 as a decorative or collector fragment; exceptional large, attractive pieces may sell for roughly $50–$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

Vivid translucent blue, glassy luster, conchoidal fracture, and irregular vesicles; no true crystal structure or cleavage. Mohs hardness is approximately 5–6, with moderate-to-high density depending on metal content. The sharp, melted-looking edges and bubbly texture indicate processed glassy material rather than a natural mineral.

Formation & geological history

Formed when molten industrial waste or glass cooled rapidly, trapping bubbles and producing a quenched amorphous texture; it has no geological age. Exact identification requires chemical testing, such as XRF, because similar blue glass can contain cobalt, copper, or synthetic pigments.

Uses & applications

Primarily a curiosity, decorative specimen, or craft material; it is not generally used as a gemstone or construction stone. Avoid handling sharp edges and do not use it for jewelry without cutting and polishing.

Geological facts

The intense blue color and frothy surface are characteristic of colored glass or slag, not typical natural blue rocks. Natural alternatives such as azurite or sodalite usually show crystalline grains, cleavage, or earthy surfaces.

Field identification & locations

Inspect for conchoidal fracture, bubbles, flow bands, and a uniformly glassy interior; these distinguish it from crystalline rock. Commonly found near historic glassworks, metal-smelting sites, dumps, or beaches receiving industrial debris.