man-made glass

Blue Goldstone

Synthetic glass with cobalt and copper inclusions

AI-generated identification · may be incorrect

Hardness: ~5.5 (Mohs scale), Color: dark blue/purple with sparkling metallic flecks, Luster: vitreous (glassy), Crystal structure: amorphous (glass) with crystalline inclusions, specific gravity: ~2.5

Hardness: ~5

Identified July 19, 2026More man-made glass →

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Physical properties

Formation & geological history

Man-made material. Originally created in Venice, Italy. Formed by melting silica, copper oxide, and other metal oxides (like cobalt or manganese for the blue color) in a reducing atmosphere.

Uses & applications

Used primarily in jewelry, cabochons, carvings, and as a decorative stone in collecting or crystal healing practices.

Geological facts

Despite its name, it contains no gold. The sparkles are typically tiny crystals of copper that precipitate out of the cooling glass. The blue version uses cobalt or manganese.

Field identification & locations

Identified by its deep color and distinct, dense, perfectly suspended metallic sparkles. It feels like glass and is often polished into smooth, tumbled shapes.