sedimentary
Agate
Silica (Chalcedony), SiO2
Hardness: 6.5-7 on the Mohs scale, Color: Multicolored with bands (brown, gray, white, red, etc.), Luster: Waxy to vitreous, Crystal structure: Microcrystalline (trigonal), Cleavage: None, Specific gravity: 2.58-2.64
- Hardness
- 6
- Color
- Multicolored with bands (brown, gray, white, red, etc
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Physical properties
Hardness: 6.5-7 on the Mohs scale, Color: Multicolored with bands (brown, gray, white, red, etc.), Luster: Waxy to vitreous, Crystal structure: Microcrystalline (trigonal), Cleavage: None, Specific gravity: 2.58-2.64
Formation & geological history
Forms primarily within cavities of volcanic and metamorphic rocks through the deposition of silica from groundwater solutions in concentric layers over long geological periods.
Uses & applications
Used in ornamental objects, jewelry, tumbled stones, leather-working burnishers, and scientific mortars and pestles.
Geological facts
Agate is one of the most popular stones used in art and healing since antiquity, named after the Achates River in Sicily where they were first found.
Field identification & locations
Identified by its distinctive banded patterns and waxy luster. Common in regions with ancient volcanic activity worldwide. Great for novice rockhounds.
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