sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
AI-generated identification · may be incorrectHardness: 6.5-7 on the Mohs scale; Color: Brown, tan, translucent; Luster: Waxy to vitreous; Crystal structure: Microcrystalline (trigonal); Cleavage: None, exhibits conchoidal fracture; Specific gravity: 2.58-2.64
- Hardness
- 6
- Color
- Brown, tan, translucent
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5-7 on the Mohs scale; Color: Brown, tan, translucent; Luster: Waxy to vitreous; Crystal structure: Microcrystalline (trigonal); Cleavage: None, exhibits conchoidal fracture; Specific gravity: 2.58-2.64
Formation & geological history
Formed within the cavities of volcanic and metamorphic rocks through the deposition of silica-rich groundwater solutions over millions of years.
Uses & applications
Used in jewelry, ornamental carvings, polished specimens, scientific instruments, and by collectors.
Geological facts
Agate is a common form of chalcedony that often displays distinct banding patterns, though solid colored variations also occur. Ancient civilizations used it for talismans and seals.
Field identification & locations
Identified by its waxy luster, conchoidal fracture, and resistance to scratching by steel. Commonly found in riverbeds, beaches, and volcanic regions worldwide.
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