mineral

Tumbled gray stone, likely gray agate or jasper

Microcrystalline quartz (chalcedony), SiO₂; exact identification requires testing

AI-generated identification · may be incorrect

Smoothly polished, opaque-to-translucent gray-brown body with cream linear banding or fractures and a waxy-to-glassy luster. Quartz hardness is about 7 Mohs; no obvious cleavage, cryptocrystalline structure, and specific gravity near 2.6.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich groundwater filled cavities or fractures in volcanic rock, later producing chalcedony bands; geological age is unknown and depends on its source deposit.

Uses & applications

Used as a lapidary stone for tumbling, cabochons, beads, and decorative objects; not typically used in construction as an individual specimen.

Geological facts

The pale lines may be natural agate banding, healed fractures, or veins, though the photograph cannot distinguish them reliably from similar jasper or quartzite.

Field identification & locations

Commonly found in volcanic terrains and gravel deposits worldwide, especially Brazil, Uruguay, Mexico, India, and the western United States. A scratch test, translucency check, and close examination of banding can help confirm chalcedony.