mineral
Tumbled agate (possibly carnelian)
Microcrystalline quartz, SiO₂; likely chalcedony
AI-generated identification · may be incorrectA smooth, polished pink-orange to brown stone with a waxy luster. Quartz hardness is 7 Mohs; trigonal crystal structure, though microscopic fibers form the visible chalcedony texture. Specific gravity is about 2.6.
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Physical properties
A smooth, polished pink-orange to brown stone with a waxy luster. Quartz hardness is 7 Mohs; trigonal crystal structure, though microscopic fibers form the visible chalcedony texture. Specific gravity is about 2.6.
Formation & geological history
Silica-rich groundwater deposited chalcedony in cavities and fractures, often in volcanic rocks; the specimen was later shaped and polished. Its exact age and source cannot be determined from the image.
Uses & applications
Used for jewelry, beads, ornaments, and collecting; agate is also used for small precision components.
Geological facts
Agate is a banded variety of chalcedony, but banding is not evident here; the reddish color may be natural iron staining.
Field identification & locations
Identify by its hardness, waxy surface, and lack of cleavage; a scratch test or closer view may distinguish agate from carnelian. Chalcedony occurs worldwide, notably in Brazil, Uruguay, India, and the western United States.
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