mineral

Polished banded agate

Agate, a banded variety of chalcedony (microcrystalline SiO₂)

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; cream, tan, and orange-red bands; waxy to vitreous luster; cryptocrystalline quartz with no visible cleavage. The specimen is rounded and polished.

Identified October 13, 2026More mineral →

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Physical properties

Hardness about 6.5–7 Mohs; cream, tan, and orange-red bands; waxy to vitreous luster; cryptocrystalline quartz with no visible cleavage. The specimen is rounded and polished.

Formation & geological history

Agate forms as silica-rich fluids deposit chalcedony in cavities and fractures, commonly in volcanic rocks. Its bands record successive mineral deposition; precise age and locality cannot be determined from the image.

Uses & applications

Used for cabochons, beads, small carvings, ornaments, and teaching collections; agate is also used for durable decorative objects and occasionally precision components.

Geological facts

Agate’s distinctive concentric or parallel bands arise from changing conditions during silica deposition, and some orange-red coloring may be enhanced by iron oxides or treatment.

Field identification & locations

Identify by hardness, waxy luster, and curved or parallel bands; it commonly occurs in volcanic geodes and silica-rich rocks worldwide. The image alone cannot establish whether the color is natural or treated.