mineral

Goldstone

Avventurina (Man-made Glass with Copper inclusions)

Hardness: 5.5-6. Color: Reddish-brown with metallic speckles. Luster: Vitreous with aventurescence. Crystal Structure: Amorphous (glass matrix) containing cubic copper crystals. Cleavage: None. Specific Gravity: 2.5-2.8.

Hardness: 5
Color: Reddish-brown with metallic speckles
Luster: Vitreous with aventurescence

Identified July 17, 2026More mineral →

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Physical properties

Formation & geological history

Goldstone is a synthetic material created in a low-oxygen reducing atmosphere. Molten glass is mixed with copper salts; as it cools slowly, copper ions precipitate into tiny, highly reflective metallic crystals. Originally perfected in 17th-century Venice.

Uses & applications

Used extensively in jewelry making (beads, cabochons), carvings, decorative ornaments, and metaphysical collecting.

Geological facts

Despite its name, goldstone contains no gold; the 'gold' appearance comes from copper. Legend says it was discovered by accident when Italian monks spilled copper filings into molten glass, though the process likely predates that story.

Field identification & locations

Identified by its uniform glittery appearance and glass-like feel. In the field, look for a smooth, non-porous surface that sparkles intensely under direct light. It is often confused with natural Sunstone but has much more uniform glitter.

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sedimentary

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Schist

Metamorphic

Potassium Feldspar (Orthoclase)

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Gypsum (variety Selenite or Alabaster)

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Mineral

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Mineral/Rock