mineral

Brown chalcedony (possibly carnelian)

Microcrystalline quartz, SiO₂; carnelian is orange-red chalcedony

AI-generated identification · may be incorrect

Small translucent brown fragment with a waxy to glassy luster and no visible cleavage; quartz hardness is about 7 Mohs. Its tiny size and surface appearance make exact identification uncertain.

Identified October 4, 2026More mineral →

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Physical properties

Small translucent brown fragment with a waxy to glassy luster and no visible cleavage; quartz hardness is about 7 Mohs. Its tiny size and surface appearance make exact identification uncertain.

Formation & geological history

Chalcedony forms as silica-rich fluids fill cavities and fractures, commonly in volcanic rocks; its age depends on the host formation.

Uses & applications

Chalcedony is used for beads, cabochons, carvings, and ornamental objects; this fragment appears too small for substantial commercial use.

Geological facts

Carnelian is the orange-red variety of chalcedony, while brown chalcedony may be sold as sard or simply brown agate depending on color and banding.

Field identification & locations

Look for hardness near 7, a waxy luster, and conchoidal fracture; a scratch test and inspection for banding can help distinguish it from glass or other minerals. Chalcedony occurs worldwide, including in volcanic regions and river gravels.