mineral

Tumbled agate/chalcedony (likely moss or plume agate)

Microcrystalline quartz, SiO₂, chiefly chalcedony with possible iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent cream, gray, brown, and bluish colors with cloudy or faintly banded internal patterns; waxy to vitreous luster and no cleavage. The smoothly rounded shape indicates tumbling and polishing.

Identified August 29, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rocks, depositing chalcedony and quartz in layers around inclusions over long periods, commonly during the Cenozoic or older volcanic episodes.

Uses & applications

Used for inexpensive cabochons, beads, carvings, ornaments, and lapidary collections; durable enough for some small decorative objects.

Geological facts

Agate is a variety of chalcedony distinguished by banding, color zoning, or inclusion patterns; exact identification from a photograph is limited because similar jasper and common chalcedony can look alike.

Field identification & locations

Common sources include Brazil, Uruguay, Mexico, India, Madagascar, and the western United States. Look for translucency, waxy luster, curved banding, and conchoidal fracture; a streak test is white, and it should resist scratching by steel.