mineral

Quartz (Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Grayish-white to tan; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.65

Hardness: 7 (Mohs scale)
Color: Grayish-white to tan
Luster: Waxy to vitreous

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Grayish-white to tan; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.65

Formation & geological history

Formed through the deposition of silica-rich fluids in cavities or veins of volcanic and sedimentary rocks. This specimen appears as a massive, microcrystalline variety likely of Cenozoic to Mesozoic origin.

Uses & applications

Used widely in manufacturing glass, ceramics, and abrasives. Cryptocrystalline varieties are used in lapidary work, jewelry, and as decorative collector pieces.

Geological facts

Quartz is one of the most abundant minerals in the Earth's crust. Chalcedony was used as early as the Bronze Age for seals and jewelry because it does not chip easily and holds fine details.

Field identification & locations

Identify by its waxy luster, lack of cleavage, and ability to scratch glass. Commonly found in gravel beds, riverbanks, and volcanic outcrops around the world.