mineral

Banded agate (polished/tumbled)

Microcrystalline quartz, SiO₂; likely banded chalcedony

AI-generated identification · may be incorrect

Waxy to vitreous luster with parallel cream, gray-green, and brown bands. Quartz hardness is about 6.5–7 Mohs; trigonal crystal structure, no visible cleavage, and specific gravity around 2.6.

Identified September 25, 2026More mineral →

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Physical properties

Waxy to vitreous luster with parallel cream, gray-green, and brown bands. Quartz hardness is about 6.5–7 Mohs; trigonal crystal structure, no visible cleavage, and specific gravity around 2.6.

Formation & geological history

Silica-rich groundwater deposited successive layers in a cavity, later lithified and polished; agate deposits occur in rocks of many ages, commonly in volcanic regions.

Uses & applications

Used for jewelry, carvings, ornaments, and collectible specimens; agate has also been used for small precision instruments.

Geological facts

Agate’s distinctive bands record changing mineral conditions during growth; colors may be enhanced by dyeing or other treatment.

Field identification & locations

Identify by its fine, curved or parallel bands and hardness sufficient to scratch glass; common sources include Brazil, Uruguay, India, and the western United States.