Man-made glass (often grouped with minerals in lapidary)

Blue Goldstone

Aventurine Glass

Hardness: 5.5-6 (Mohs scale); Color: Deep midnight blue with vibrant blue or violet sparkles; Luster: Vitreous (glassy); Crystal Structure: Amorphous (non-crystalline glass); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.5-2.8

Hardness: 5
Color: Deep midnight blue with vibrant blue or violet sparkles
Luster: Vitreous (glassy)

Identified April 20, 2026More man-made glass (often grouped with minerals in lapidary) →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Goldstone is a synthetic glass created in a low-oxygen reducing atmosphere. It was originally discovered in 17th-century Venice by the Miotti family. The blue variety is created by adding cobalt or manganese to the silica melt, which causes the metallic copper or other metal oxides to crystallize into tiny flakes.

Uses & applications

Primarily used for decorative purposes, jewelry (pendants, beads, cabochons), carving small figurines, and as a popular stone for crystal healing and collector sets.

Geological facts

Despite its name, it contains no gold. Its 'glitter' comes from the inclusion of tiny metallic crystals. While man-made, it is treated as a gemstone in the lapidary world and has been produced for centuries.

Field identification & locations

Identify by its uniform, intense sparkling effect (aventurescence) and smooth, glass-like surface. It will not be found in nature; it is always the result of human manufacturing. Look for the characteristic conchoidal (shell-like) fracture if chipped.

Other man-made glass (often grouped with minerals in lapidary) specimens

See all

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

Mineraloid

Cullet (Slag Glass)

Amorphous Silica (SiO2) with various metal oxide colorants

mineraloid / anthropogenic

Slag Glass

Anthropogenic Amorphous Silicon Dioxide

mineral

Greenish Metamorphic Rock (likely containing epidote or chlorite)

Metamorphic rock, possibly epidosite or greenstone

Metamorphic

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial byproduct)

mineraloid

Opalite (Synthetic Opalized Glass)

Synthetic Silicon Dioxide (SiO2) glass

mineral