mineral

Tumbled chalcedony or agate

Microcrystalline quartz (SiO₂), likely porous/botryoidal chalcedony with possible agate banding

AI-generated identification · may be incorrect

Opaque tan-brown and cream, waxy to dull luster, hardness about 6.5–7 Mohs, massive microcrystalline structure, no visible cleavage, and specific gravity near 2.6. The rounded shape indicates tumbling or natural abrasion.

Identified September 22, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater deposited quartz fibers in cavities, fractures, or porous volcanic rock; later weathering and abrasion rounded it. The specimen’s exact geological age and locality cannot be determined from the image.

Uses & applications

Used as a decorative stone, cabochon, bead, carving material, and lapidary specimen; comparable tumbled pieces are generally inexpensive.

Geological facts

Cream porous patches may represent botryoidal chalcedony, weathered inclusions, or a druzy-like silica texture rather than true agate banding.

Field identification & locations

Identify by its glassy/waxy feel, quartz-like hardness, lack of cleavage, and inability to scratch it with a steel knife; test cautiously because surface coatings or softer inclusions may mislead. Common worldwide, especially in volcanic terrains and silica-rich cavities.