mineral
Chalcedony (Botryoidal)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 (Mohs), Color: White/Grey, Luster: Waxy to Vitrous, Crystal Structure: Hexagonal (Trigonal) - Cryptocrystalline, Fracture: Conchoidal, Specific Gravity: 2.6-2.64.
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs), Color: White/Grey, Luster: Waxy to Vitrous, Crystal Structure: Hexagonal (Trigonal) - Cryptocrystalline, Fracture: Conchoidal, Specific Gravity: 2.6-2.64.
Formation & geological history
Formed from the precipitation of silica-rich groundwater in cavities of volcanic and sedimentary rocks. Typically occurs as a secondary mineral in geodes or as a replacement mineral.
Uses & applications
Used primarily in lapidary arts, jewelry (cabochons), and for ornamental carvings. Industrial uses include use as an abrasive in specific polishing processes.
Geological facts
Chalcedony is a cryptocrystalline form of silica, meaning its crystals are too small to be seen under a normal microscope. The 'bumpy' texture seen on this specimen is known as a botryoidal (grape-like) growth habit.
Field identification & locations
Identify in the field by its waxy luster, hardness (it will scratch glass), and its distinctive mammillary or botryoidal surface texture. Commonly found in desert regions or volcanic areas.
