mineral

Small polished agate (likely banded chalcedony)

Chalcedony, microcrystalline quartz (SiO₂)

AI-generated identification · may be incorrect

Opaque to translucent cream, tan, and brown; waxy to vitreous luster, Mohs hardness 6.5–7, trigonal quartz structure, no cleavage, conchoidal fracture. The image shows a small rounded, polished specimen; exact identification is uncertain from the photograph.

Identified October 11, 2026More mineral →

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Physical properties

Formation & geological history

Agate forms as silica-rich fluids fill cavities in volcanic rock and deposit successive layers. Deposits range from ancient to geologically recent, depending on the host rock.

Uses & applications

Used for beads, cabochons, ornaments, and small collectibles; agate is also used in some precision components and decorative stonework.

Geological facts

Agate is a variety of chalcedony, and its visible bands form through repeated mineral deposition.

Field identification & locations

Look for waxy luster, hardness, and possible curved bands; common sources include Brazil, Uruguay, India, and the western United States. A field photograph alone cannot confirm the specimen’s identity.