mineral

Banded Chalcedony (Agate)

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Pale blue-green to white with brownish-tan banding. Luster: Vitreous to waxy. Structure: Microcrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Pale blue-green to white with brownish-tan banding
Luster: Vitreous to waxy

Identified July 6, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily from the deposition of silica-rich groundwater in the volcanic cavities (vesicles) of igneous rocks or in sedimentary layers. These banded structures occur over long periods as mineral content in the water changes.

Uses & applications

Popular for use in jewelry (cabochons), ornamental carvings, stone marbles, and as a healing stone in holistic practices.

Geological facts

This specimen appears to be a spherical polished piece or a stone marble. Agate was one of the first materials used by prehistoric humans for tools and ornaments due to its durability and aesthetic appeal.

Field identification & locations

Look for the characteristic concentric or planar bands and a translucent appearance when held to light. Can be found globally in volcanic environments; common locations include Brazil, India, and the United States.

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