mineral
Chalcedony nodule (likely agate)
Microcrystalline quartz, SiO₂; banded varieties are agate
AI-generated identification · may be incorrectHoney-brown, translucent to opaque, with a waxy luster and subtle curved banding around a central cavity. Mohs hardness 6.5–7; trigonal quartz structure, no cleavage, conchoidal fracture; specific gravity about 2.6.
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Physical properties
Honey-brown, translucent to opaque, with a waxy luster and subtle curved banding around a central cavity. Mohs hardness 6.5–7; trigonal quartz structure, no cleavage, conchoidal fracture; specific gravity about 2.6.
Formation & geological history
Silica-rich groundwater deposited quartz in a cavity or fracture, likely in volcanic rock; the precise age and locality cannot be determined from the image.
Uses & applications
Often cut and polished for cabochons, beads, ornaments, and teaching collections; chalcedony is also used for small decorative objects.
Geological facts
Agate is a banded form of chalcedony, while chalcedony itself is too fine-grained for individual crystals to be seen unaided.
Field identification & locations
Look for waxy translucence, hardness sufficient to scratch glass, and curved internal bands; common in volcanic regions and stream gravels. The photo alone cannot confirm agate or establish provenance.
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