mineral

Polished agate spheres

Agate, a banded variety of microcrystalline quartz (SiO₂)

AI-generated identification · may be incorrect

The display shows polished, translucent spheres in pink, yellow-orange, and blue-gray, with cloudy or banded patterns and a vitreous luster. Quartz has Mohs hardness 7, trigonal crystal structure, and no cleavage; specific gravity is about 2.6.

Identified October 6, 2026More mineral →

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Physical properties

Formation & geological history

Agate forms as silica-rich fluids fill cavities in volcanic rocks, depositing microscopic quartz in layers. The specimens’ geological ages and exact origins cannot be determined from the photo.

Uses & applications

Agate is used for jewelry, ornamental carvings, spheres, and decorative objects; its hardness also makes it suitable for durable polished pieces.

Geological facts

Agate’s colors and patterns vary with trace impurities and successive silica layers; some commercial material may be dyed, so color alone does not establish its origin.

Field identification & locations

Identify agate by its waxy-to-glassy polish, translucency, and fine, often curved bands or cloudy layers. It occurs worldwide, commonly in volcanic rocks; the pictured spheres are polished, so field texture is not visible.