mineral

Chalcedony (Carnelian Agate pebble)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Orange, reddish-brown, or peach; Luster: Waxy to vitreous; Crystal Structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58–2.64

Hardness: 6
Color: Orange, reddish-brown, or peach
Luster: Waxy to vitreous

Identified May 31, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Orange, reddish-brown, or peach; Luster: Waxy to vitreous; Crystal Structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.58–2.64

Formation & geological history

Formed through the deposition of silica from groundwater in cavities of igneous or sedimentary rocks. This specimen is a water-worn river pebble, likely aged from several million to hundreds of millions of years depending on source geology.

Uses & applications

Commonly used in lapidary work, jewelry (beads, cabochons), and as smooth decorative pocket stones or aquarium gravel.

Geological facts

Carnelian has been used as a gemstone since antiquity; it was notably used by the Romans to make seal rings and by the Ancient Egyptians for amulets.

Field identification & locations

Identify in the field by its waxy luster, translucency when held to light, and smooth, rounded surface from water erosion. Found in gravel beds, shorelines, and basaltic regions worldwide.

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