mineral
Chalcedony (Agate/Jasper mix)
Cryptocrystalline Sillimanite (Quartz) - SiO2
AI-generated identification · may be incorrectHardness: 6.5-7 on Mohs scale. Color: Yellow-orange to milky white when backlit. Luster: Waxy to vitreous. Crystal structure: Hexagonal (trigonal) cryptocrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.
- Hardness
- 6
- Color
- Yellow-orange to milky white when backlit
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 6.5-7 on Mohs scale. Color: Yellow-orange to milky white when backlit. Luster: Waxy to vitreous. Crystal structure: Hexagonal (trigonal) cryptocrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.
Formation & geological history
Formed from the deposition of silica from groundwater in cavities of igneous rocks or through sedimentary processes. Often associated with volcanic environments where silica-rich fluids cool and solidify over thousands of years.
Uses & applications
Used primarily in lapidary arts for jewelry, carvings, and tumbled stones. Historically used for making tools and weapons due to its sharpness and toughness. Also popular for decorative metaphysical displays.
Geological facts
The term 'chalcedony' comes from the ancient Greek town of Chalcedon. When it shows banding, it is called Agate; when it is opaque and colorful, it is Jasper. This specific specimen exhibits high translucency, typical of high-quality quartz-based minerals.
Field identification & locations
Identify in the field by checking for a waxy texture, conchoidal (shell-like) fractures, and its ability to scratch glass. It is commonly found in riverbeds, desert pavements, and volcanic regions. It remains one of the most common yet diverse minerals for collectors.
