mineral

Chalcedony Pebble

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: translucent white to pale grey with yellowish inclusions; Luster: waxy to vitreous; Crystal structure: Trigonal (microcrystalline); Cleavage: none; Specific gravity: 2.58-2.64

Hardness: 6
Color: translucent white to pale grey with yellowish inclusions
Luster: waxy to vitreous

Identified July 6, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the deposition of silica-rich water in volcanic or sedimentary cavities. This specimen exhibits water-worn rounding, suggesting it was found in a riverbed or coastal environment.

Uses & applications

Commonly used for lapidary work, jewelry (cabochons), and as aquarium or decorative stones.

Geological facts

Chalcedony is the botanical name for a large family of stones including agate, jasper, and carnelian. It was used in antiquity for cylinder seals and cameos due to its durability.

Field identification & locations

Identified in the field by its waxy luster, conchoidal fracture, and translucency. It will scratch steel but not topaz. Common in gravel deposits globally.