mineral

Botryoidal Chalcedony / Agate

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, typically brown, gray, or translucent, waxy to vitreous luster, cryptocrystalline structure, no cleavage, specific gravity of 2.60 to 2.65.

Identified July 28, 2026More mineral →

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Physical properties

Hardness of 7 on the Mohs scale, typically brown, gray, or translucent, waxy to vitreous luster, cryptocrystalline structure, no cleavage, specific gravity of 2.60 to 2.65.

Formation & geological history

Forms in hydrothermal veins or cavities in volcanic rocks where silica-rich groundwater deposits microcrystalline quartz in rounded, grape-like (botryoidal) clusters over millions of years.

Uses & applications

Used primarily in lapidary arts, ornamental carvings, gemstone collections, and occasionally in jewelry making.

Geological facts

The botryoidal habit forms when multiple spherical crystal aggregates grow close together, resembling a bunch of grapes.

Field identification & locations

Can be identified in the field by its distinct grape-like rounded surface texture, conchoidal fracture, and high hardness capable of scratching glass. Found worldwide in volcanic regions.