mineral

Tumbled Chalcedony

Quartz (Silicon Dioxide - SiO2)

Hardness: 6.5 - 7 on Mohs scale. Color: Translucent grayish-brown, tan, or grayish-purple. Luster: Waxy to vitreous. Crystal Structure: Microcrystalline aggregate (Trigonal). Cleavage: None, conchoidal fracture. Specific Gravity: 2.6 - 2.64.

Hardness: 6
Color: Translucent grayish-brown, tan, or grayish-purple
Luster: Waxy to vitreous

Identified July 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed through low-temperature deposition of silica dissolved in percolating groundwater inside volcanic cavities, sedimentary beds, or altered rocks. Tumbled and smooth finish achieved via mechanical rock polishing.

Uses & applications

Popular in rock tumbling, wire-wrapping jewelry, pocket stones, decorative display, and metaphysical collecting.

Geological facts

Chalcedony is a cryptocrystalline variety of quartz, meaning its crystals are too small to be seen without high magnification. Variants include agate, jasper, onyx, and carnelian depending on banding, inclusions, and color.

Field identification & locations

Field identification relies on its waxy luster, smooth tumbled texture, hardness (scratches glass), and translucent to sub-translucent appearance. Commonly found worldwide in volcanic basalt beds, gravel pits, and riverbeds.