mineral

Polished blue stone, likely blue chalcedony or agate

Microcrystalline quartz (SiO₂), possibly chalcedony; identification uncertain from the photo

AI-generated identification · may be incorrect

Glossy, rounded and opaque-to-translucent blue with darker patches; quartz hardness 6.5–7, Mohs, and trigonal crystal structure at the microscopic level. The smooth finish appears polished, so natural luster and fracture are not visible.

Identified October 8, 2026More mineral →

Explore Polished blue stone, likely blue chalcedony or agate in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Chalcedony forms as silica-rich fluid fills cavities and fractures, commonly in volcanic rocks; its age depends on the host deposit. Blue color may be natural or enhanced by dye or coating.

Uses & applications

Used for cabochons, beads, jewelry, and small decorative objects; this polished piece may be a bead or cabochon.

Geological facts

The image does not show diagnostic banding or other details needed to distinguish agate from other blue polished stones.

Field identification & locations

Look for hardness near 7, a waxy luster, and conchoidal fracture on an unpolished surface; color alone is unreliable. Chalcedony occurs worldwide, including Brazil, Uruguay, India, and the United States.