mineral

Brown chalcedony pebble

Chalcedony, microcrystalline quartz (SiO₂)

AI-generated identification · may be incorrect

Smooth, rounded, translucent-to-opaque brown with a waxy luster. Quartz has Mohs hardness 7 and a trigonal crystal structure at microscopic scale; no visible cleavage and conchoidal fracture.

Identified October 16, 2026More mineral →

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Physical properties

Smooth, rounded, translucent-to-opaque brown with a waxy luster. Quartz has Mohs hardness 7 and a trigonal crystal structure at microscopic scale; no visible cleavage and conchoidal fracture.

Formation & geological history

Silica-rich fluids deposited microscopic quartz fibers in rock cavities or fractures; the pebble was later rounded by water or abrasion. Chalcedony forms in many geological periods and settings.

Uses & applications

Used for beads, cabochons, carvings, and decorative objects; this small pebble is mainly a collecting specimen.

Geological facts

Brown color commonly comes from iron oxides or other impurities. The image does not show enough detail to distinguish chalcedony confidently from other brown stones.

Field identification & locations

Look for hardness near 7, a waxy surface, and curved fracture surfaces; common in river gravels and weathered volcanic regions. Exact identification may require testing.