mineral

Quartz (Agate/Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: Brownish, amber, translucent to opaque. Luster: Vitreous to waxy. Crystal structure: Trigonal (microcrystalline/cryptocrystalline variety of quartz). Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.60 to 2.65.

Hardness: 7 on the Mohs scale
Color: Brownish, amber, translucent to opaque
Luster: Vitreous to waxy

Identified August 1, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, cavities of volcanic rocks, and sedimentary environments through the deposition of silica-rich groundwater over millions of years.

Uses & applications

Used in lapidary arts, wire wrapping, jewelry making, ornamental carvings, and as a popular specimen for mineral collectors.

Geological facts

Chalcedony and its varieties like agate have been used by humans since Neolithic times to create tools, beads, and weapons due to its conchoidal fracture which produces sharp edges when struck.

Field identification & locations

Can be identified in the field by its waxy luster, hardness (will scratch glass), and lack of cleavage with a smooth conchoidal break. Commonly found in riverbeds, gravel bars, and areas with volcanic rock formations.