man-made glass

Blue Goldstone

Synthetic Aventurescent Glass (Cobalt-doped soda-lime glass)

AI-generated identification · may be incorrect

Hardness: 5.5-6 (Mohs scale); Color: Deep midnight blue with tiny silvery-white metallic specks; Luster: Vitreous; Crystal Structure: Amorphous (glass); Cleavage: None/Conchoidal fracture; Specific Gravity: ~2.5-2.8

Hardness: 5
Color: Deep midnight blue with tiny silvery-white metallic specks
Luster: Vitreous

Identified June 28, 2026More man-made glass →

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Physical properties

Formation & geological history

Produced in a low-oxygen reducing atmosphere where molten glass is infused with cobalt (for blue) and metallic crystals; despite myths of monastic origins, the modern process was popularized in 17th-century Venice, Italy.

Uses & applications

Primarily used for costume jewelry (cabochons, beads), decorative carvings, and metaphysical/healing crystal practices.

Geological facts

Although often sold alongside natural gemstones, Goldstone is a synthetic material. The 'stars' inside blue goldstone are actually tiny crystals of metallic cobalt or other metal oxides suspended within the glass.

Field identification & locations

Identify by its perfectly uniform distribution of metallic inclusions and deep blue base color; it is never found in nature. Tumbled stones like the one pictured are common in gift shops and crystal sets.