man-made glass

Blue Goldstone

Aventurine Glass (SiO2 with Cobalt/Copper inclusions)

Hardness: 5.5-6 (Mohs scale); Color: Deep midnight blue with sparking metallic inclusions; Luster: Vitreous (glassy); Crystal structure: Amorphous; Cleavage: None (conchoidal fracture); Specific gravity: 2.4 - 2.5.

Hardness: 5
Color: Deep midnight blue with sparking metallic inclusions
Luster: Vitreous (glassy)

Identified March 15, 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 rediscovered or popularized in 17th-century Venice by the Miotti family. The blue variety is created by substituting copper with cobalt or manganese during the melting of silica, borax, and other glass-forming ingredients.

Uses & applications

Used primarily in jewelry (cabochons, beads), decorative carvings, figurines, and as a popular stone for crystal healing and metaphysical collecting.

Geological facts

Despite its name, it contains no gold. It is often called 'the stone of ambition.' While it is glass, the 'aventurescence' effect is caused by tiny metallic crystals that precipitate out of the glass as it cools slowly.

Field identification & locations

Identification is easy due to its perfectly uniform distribution of 'glitter' and smooth, glassy surface. You will not find this in a natural geological setting; it is exclusively found in retail shops and lapidary markets. Look for bubbles or a conchoidal (shell-like) fracture pattern if chipped.

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