mineral
Tumbled chalcedony (likely agate)
Microcrystalline quartz, SiO₂; possibly iron-stained chalcedony
AI-generated identification · may be incorrectRounded, translucent gray-beige stone with yellow-brown patches; vitreous to waxy luster and no visible cleavage. Quartz hardness is 7 Mohs, but the image does not show enough detail to confirm agate banding or identify the exact variety.
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Physical properties
Rounded, translucent gray-beige stone with yellow-brown patches; vitreous to waxy luster and no visible cleavage. Quartz hardness is 7 Mohs, but the image does not show enough detail to confirm agate banding or identify the exact variety.
Formation & geological history
Chalcedony forms when silica-rich fluids deposit quartz in cavities and fractures, often in volcanic rocks; iron oxides can create yellow-brown coloration. Its age and original geological setting cannot be determined from the photograph.
Uses & applications
Tumbled chalcedony is used in jewelry, ornaments, and lapidary collections; larger agate pieces may be cut or polished for display.
Geological facts
Agate is a banded variety of chalcedony, but banding is not clearly visible here.
Field identification & locations
The smooth rounded shape suggests tumbling or natural water-wear. Check for hardness and internal banding; common sources include Brazil, Uruguay, India, and the western United States.
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