mineral
Botryoidal Chalcedony
Silicon Dioxide (SiO2)
Hardness of 6.5 to 7 on the Mohs scale, color ranges from grey to brownish-yellow, waxy to vitreous luster, microcrystalline (cryptocrystalline) quartz structure, conchoidal fracture with no true cleavage, and a specific gravity of 2.60 to 2.65.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, color ranges from grey to brownish-yellow, waxy to vitreous luster, microcrystalline (cryptocrystalline) quartz structure, conchoidal fracture with no true cleavage, and a specific gravity of 2.60 to 2.65.
Formation & geological history
Formed at low temperatures from silica-rich aqueous solutions precipitating in cavities, veins, or fractures in rocks, often occurring in volcanic or sedimentary environments over geological time scales.
Uses & applications
Used in lapidary arts, wire-wrapping, ornamental carvings, and jewelry making, as well as being a prized specimen for mineral collectors.
Geological facts
The botryoidal habit forms when multiple mineral spheres grow close together, resembling a bunch of grapes due to surface tension and radial crystal growth.
Field identification & locations
Easily identified by its distinctive grape-like or bubbly rounded surface texture combined with high quartz hardness. Found worldwide, particularly in areas with volcanic activity or ancient hydrothermal systems.
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mineral