mineral

Polished agate (likely moss or plume agate)

Microcrystalline quartz, SiO₂; chalcedony with brown iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; white to translucent with brown inclusions and a waxy-to-glassy luster. Trigonal quartz structure; no visible cleavage, with conchoidal fracture. The photo shows a polished, rounded specimen, so precise variety is uncertain.

Identified October 15, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater deposited chalcedony in cavities, with iron-bearing inclusions producing the brown markings. Agates form in volcanic rocks and other cavities over geological time; the specimen’s age and locality cannot be determined from the image.

Uses & applications

Used for jewelry, cabochons, ornaments, and collecting; agate is also used for small decorative objects and, historically, precision components.

Geological facts

Agate is a banded or patterned variety of chalcedony; its colors and inclusions arise from trace minerals and changing deposition conditions.

Field identification & locations

Look for hardness near 7, waxy luster, and translucent chalcedony; a scratch test or magnification can help distinguish it from glass or resin. Agates occur worldwide, especially in volcanic regions.