gemstone
Agate
Silicon dioxide (Chalcedony), SiO2
Hardness: 6.5-7 on Mohs scale; Color: Brown with white banding; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None
- Hardness
- 6
- Color
- Brown with white banding
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: Brown with white banding; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None
Formation & geological history
Formed by the deposition of silica from groundwater in the cavities of igneous and sedimentary rocks, typically over millions of years.
Uses & applications
Used in ornamental objects, jewelry, and lapidary art.
Geological facts
Agate is a common rock formation, cryptocrystalline form of silica, chiefly presented as bands in chalcedony.
Field identification & locations
Can be identified in the field by its distinct waxy luster and concentric color banding. Found worldwide, particularly in volcanic rock cavities.
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