mineral

Tumbled chalcedony/agate (probable)

Microcrystalline quartz, SiO₂; likely banded or plume agate with iron-oxide staining

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; waxy to dull luster, translucent white-gray body with lavender, tan, yellow, and gray patches. Quartz is trigonal microscopically, with no cleavage and conchoidal fracture; the rounded surface indicates tumbling.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater filled cavities or fractures in volcanic rock, depositing layered chalcedony over time; iron oxides produced the ochre coloration. The exact geological age cannot be determined from the photograph.

Uses & applications

Used as a lapidary stone for cabochons, carvings, jewelry, and decorative pieces; attractive tumbled specimens are collected.

Geological facts

Agate is identified by contrasting chalcedony bands, while plume or moss-like internal patterns may reflect mineral inclusions. The photograph is insufficient to distinguish agate confidently from jasper or common chalcedony.

Field identification & locations

Common sources include Brazil, Uruguay, Mexico, India, Madagascar, and the western United States. Look for translucency, curved banding, waxy luster, and hardness sufficient to scratch glass; a white streak and lack of fizz in dilute acid support quartz.