mineral
Polished brown agate (likely)
Microcrystalline quartz, SiO₂ (chalcedony; agate variety)
AI-generated identification · may be incorrectPolished, translucent-to-opaque brown material with possible dark inclusions; vitreous luster. Quartz hardness is 6.5–7 Mohs, trigonal crystal structure, and no cleavage; the image alone cannot confirm agate banding or exact variety.
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Physical properties
Polished, translucent-to-opaque brown material with possible dark inclusions; vitreous luster. Quartz hardness is 6.5–7 Mohs, trigonal crystal structure, and no cleavage; the image alone cannot confirm agate banding or exact variety.
Formation & geological history
Forms as silica-rich fluid fills cavities and fractures, depositing chalcedony in layers. Agates occur in volcanic and other rocks across many geological ages.
Uses & applications
Used for jewelry, cabochons, ornaments, and collectibles; agate is also used for small decorative and precision objects.
Geological facts
Agate is valued for its patterns, though this piece appears uniformly brown and may be another variety of chalcedony or polished stone.
Field identification & locations
Common sources include Brazil, Uruguay, India, and the United States. Field identification relies on hardness, waxy-to-vitreous luster, and characteristic banding; polishing can obscure diagnostic surface features.
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