mineral

Quartz-rich pebble, possibly agate or chalcedony

Microcrystalline quartz (SiO₂), identification uncertain from the image

AI-generated identification · may be incorrect

Small rounded tan-brown specimen with a mottled, partly translucent surface and dull-to-waxy luster. Quartz has Mohs hardness 7 and trigonal crystal structure; the pebble’s exact texture and cleavage cannot be determined visually.

Identified October 13, 2026More mineral →

Explore Quartz-rich pebble, possibly agate or chalcedony in the encyclopedia →

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Physical properties

Formation & geological history

Likely formed as silica-rich material in a vein or cavity and later rounded by transport in water. Its geological age and precise formation setting cannot be established from the photograph.

Uses & applications

If confirmed as agate or chalcedony, it may be polished for jewelry or kept as a collector’s pebble; common quartz-rich pebbles have little industrial value individually.

Geological facts

Agate is a banded variety of chalcedony, but distinct banding is not clearly visible here.

Field identification & locations

A rounded shape suggests water wear; a fresh surface, hardness test, and transmitted-light inspection can help distinguish chalcedony from other stones. Quartz-rich pebbles occur in river and beach gravels worldwide.