gemstone

Polished banded agate (likely picture jasper or petrified wood)

Microcrystalline quartz, SiO₂, with iron-oxide and clay inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent to opaque, brown, cream, gray-green, and rust-red bands; vitreous to waxy luster; cryptocrystalline quartz with no cleavage and conchoidal fracture.

Identified August 19, 2026More gemstone →

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Physical properties

Hardness 6.5–7 Mohs; translucent to opaque, brown, cream, gray-green, and rust-red bands; vitreous to waxy luster; cryptocrystalline quartz with no cleavage and conchoidal fracture.

Formation & geological history

Silica-rich groundwater filled cavities or replaced organic material in volcanic or sedimentary rock, depositing layered chalcedony and iron oxides over time. Exact age and locality cannot be determined from the image.

Uses & applications

Used as a decorative slab, cabochon, bookend, or lapidary specimen; generally modest commercial value unless patterns, translucency, or provenance are exceptional.

Geological facts

The sharply curved fracture surfaces and fine internal banding are characteristic of chalcedony-rich material. Its appearance may overlap with petrified wood, which requires visible cellular or grain-like structure for confident identification.

Field identification & locations

Look for fine parallel or concentric bands, waxy luster, conchoidal fracture, and hardness sufficient to scratch ordinary glass. Common sources include Brazil, Uruguay, Mexico, Madagascar, and the western United States.