mineral

Tumbled agate, likely carnelian/chalcedony

Microcrystalline quartz (SiO₂), chalcedony with iron-oxide staining

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent cream, honey, and brown coloration; waxy to vitreous luster; cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded shape and glossy surface indicate tumbling and polishing.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rock, depositing chalcedony and sometimes iron oxides in layers or patches. Agate formation spans many geological ages, commonly from Paleozoic to Cenozoic volcanic environments.

Uses & applications

Used as an inexpensive ornamental stone for cabochons, beads, carvings, and polished specimens; durable enough for decorative objects and minor jewelry.

Geological facts

Agate is a variety of chalcedony rather than a separate mineral species. Its translucency and iron staining can resemble common carnelian, but distinct banding is subtle or absent in this specimen.

Field identification & locations

Identify by its very fine texture, waxy polish, translucency, quartz hardness, and absence of cleavage; it should scratch glass but not be scratched by a steel knife. Common sources include Brazil, Uruguay, India, Madagascar, and the United States.