mineral
Polished dendritic agate pebble
Chalcedony (microcrystalline SiO₂) with dark manganese- or iron-oxide dendrites
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; pale gray-white with dark branching inclusions and a waxy to vitreous polish. Microcrystalline quartz; no visible cleavage, conchoidal fracture; specific gravity about 2.6.
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Physical properties
Hardness about 6.5–7 Mohs; pale gray-white with dark branching inclusions and a waxy to vitreous polish. Microcrystalline quartz; no visible cleavage, conchoidal fracture; specific gravity about 2.6.
Formation & geological history
Silica-rich fluids deposited chalcedony in rock cavities or fractures; dendritic oxides formed along cracks during mineral growth. Agate formation spans many geological ages and settings.
Uses & applications
Used for beads, cabochons, ornaments, and mineral collecting; this small polished specimen has modest value.
Geological facts
The dark, plant-like patterns are mineral dendrites, not fossils or plant remains.
Field identification & locations
Look for translucent-to-opaque chalcedony with branching, fern-like inclusions; common sources include India, Brazil, Uruguay, and the western United States. The photo is consistent with dendritic agate, though exact locality cannot be determined visually.
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