gemstone

Polished agate or chalcedony cabochon (probable)

Microcrystalline quartz, SiO₂; likely translucent chalcedony with subtle agate banding

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; blue-gray to smoky translucent color with cream/golden internal zones; waxy to vitreous luster; cryptocrystalline quartz, no visible cleavage, specific gravity about 2.60–2.65.

Identified August 15, 2026More gemstone →

Explore Polished agate or chalcedony cabochon (probable) in the encyclopedia →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rocks, commonly producing layered chalcedony and agate. Individual pieces may range from Cretaceous to recent, depending on locality.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary specimens; common polished pieces generally have modest value.

Geological facts

The flowing color pattern and rounded polished surface are consistent with chalcedony, though the image is too blurred for confident locality or variety identification.

Field identification & locations

Field agate is recognized by concentric or irregular translucent bands, waxy luster, and resistance to scratching; common sources include Brazil, Uruguay, Mexico, India, Madagascar, and the western United States.