man-made glass

Blue Goldstone

Aventurine Glass

Hardness: 5.5-6 (Mohs scale); Color: Deep midnight blue with glittering cobalt/silver specks; Luster: Vitreous (glassy); Crystal Structure: Amorphous (non-crystalline glass); Specific Gravity: 2.5-2.8

Hardness: 5
Color: Deep midnight blue with glittering cobalt/silver specks
Luster: Vitreous (glassy)

Identified July 1, 2026More man-made glass →

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Physical properties

Formation & geological history

Goldstone is a synthetic material created in a low-oxygen reducing atmosphere. It was originally invented in 17th-century Venice by the Miotti family. It forms as cobalt or other metal oxides are added to molten glass, which then crystallize into tiny metallic platelets upon cooling.

Uses & applications

Primarily used in jewelry making (beads, cabochons), decorative carvings, meditation points, and as a popular specimen for crystal collectors and 'metaphysical' practitioners.

Geological facts

Despite the name, Blue Goldstone contains no actual gold; the 'glitter' in the blue variety is typically produced by cobalt or manganese. Legend says it was discovered by accident when Italian monks spilled copper filings into a vat of molten glass.

Field identification & locations

Identify by its uniform distribution of glittering metallic triangles or dots suspended in a dark blue translucent glass. Since it is man-made, it is not found in nature/the field, but is common in gem and mineral shops worldwide.