mineral

Polished agate (likely chalcedony)

Microcrystalline quartz, SiO₂; agate is banded chalcedony

AI-generated identification · may be incorrect

Translucent brown-green polished stone with a waxy to vitreous luster; quartz crystal structure, Mohs hardness 6.5–7, no cleavage, specific gravity about 2.6. The image does not show enough detail to confirm agate banding or identify any treatment.

Identified October 2, 2026More mineral →

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Physical properties

Formation & geological history

Chalcedony forms as silica precipitates in cavities and fractures, commonly in volcanic rocks; agate deposits span many geological ages. Its exact age and locality cannot be determined from the image.

Uses & applications

Used for cabochons, jewelry, ornaments, and decorative objects; agate is also used for small precision components.

Geological facts

Agate is a variety of chalcedony, not a separate mineral species; distinctive curved or concentric bands are common but not visible here.

Field identification & locations

Look for translucent edges, fine banding, and hardness sufficient to scratch glass; common sources include Brazil, Uruguay, India, and the western United States. A locality or reliable identification requires closer examination.