mineral
Chalcedony (Agate / Jasper Specimen)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 6.5 - 7 on Mohs scale. Color: Brownish-tan, yellowish, and greenish hues. Luster: Waxy to vitreous. Crystal system: Trigonal (microcrystalline/cryptocrystalline aggregate). Cleavage: None, conchoidal fracture. Specific gravity: 2.58 - 2.64.
- Hardness
- 6
- Color
- Brownish-tan, yellowish, and greenish hues
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5 - 7 on Mohs scale. Color: Brownish-tan, yellowish, and greenish hues. Luster: Waxy to vitreous. Crystal system: Trigonal (microcrystalline/cryptocrystalline aggregate). Cleavage: None, conchoidal fracture. Specific gravity: 2.58 - 2.64.
Formation & geological history
Forms in low-temperature hydrothermal environments, volcanic rocks, and sedimentary beds as silica-rich fluids precipitate into cavities or replace organic materials over millions of years.
Uses & applications
Used in lapidary arts, jewelry, cabochon cutting, decorative carvings, and as collectible rockhound specimens.
Geological facts
Cryptocrystalline quartz varieties like agate and jasper are made of micro-fibrous intergrowths of quartz and moganite, resulting in durable, smooth-fracturing stones.
Field identification & locations
Identify in the field by its hardness (scratches glass), lack of visible crystalline grain with the naked eye, and distinctive waxy luster on fractured surfaces. Common along riverbeds, gravel deposits, and volcanic terrains worldwide.
