mineral
Botryoidal Chalcedony / Agate
Silicon Dioxide (SiO2)
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 More mineral →
Explore Botryoidal Chalcedony / Agate in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
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.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Soil with Mineral Detritus and Quartz Fragments
Regolith / Silicate Mineral Aggregate
sedimentary
Limonite / Goethite (Iron Ore Mineral nodule)
FeO(OH)·nH2O / FeO(OH)
mineral
Schist
Schist
Metamorphic
Septarian Pebble
Septarian nodule / Concretion
sedimentary
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral