mineral

Botryoidal Chalcedony (Geode fragment)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: White to translucent gray; Luster: Waxy to vitreous; Structure: Cryptocrystalline (hexagonal system); No cleavage; Specific gravity 2.6

Hardness: 6
Color: White to translucent gray
Luster: Waxy to vitreous

Identified June 29, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: White to translucent gray; Luster: Waxy to vitreous; Structure: Cryptocrystalline (hexagonal system); No cleavage; Specific gravity 2.6

Formation & geological history

Formed by the precipitation of silica from groundwater in cavities of volcanic or sedimentary rocks. The 'bubbly' botryoidal texture occurs as mineral layers grow outward from multiple centers.

Uses & applications

Used primarily as collector specimens, lapidary material for cabochons or beads, and in ornamental carvings.

Geological facts

The term 'botryoidal' is derived from the Greek word 'botrys', meaning a bunch of grapes. Chalcedony is the cryptocrystalline form of quartz.

Field identification & locations

Identify by its characteristic grape-like spherical clusters and extreme hardness (cannot be scratched by a steel knife). Commonly found in desert regions or volcanic basalt flows.