mineral
Chalcedony (likely carnelian or jasper)
Microcrystalline quartz, SiO₂; iron-bearing varieties produce red-orange colors
AI-generated identification · may be incorrectHardness 6.5–7 Mohs; waxy to dull luster, reddish-orange and brown coloration, translucent edges, conchoidal fracture, and no cleavage. The specimen appears rough and naturally fractured, with possible brecciated or iron-stained texture.
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Physical properties
Hardness 6.5–7 Mohs; waxy to dull luster, reddish-orange and brown coloration, translucent edges, conchoidal fracture, and no cleavage. The specimen appears rough and naturally fractured, with possible brecciated or iron-stained texture.
Formation & geological history
Forms when silica-rich groundwater fills cavities and fractures, later cementing into chalcedony; iron oxides create the warm red colors. Formation may occur in volcanic rocks from the Cenozoic or older periods, depending on locality.
Uses & applications
Used for carvings, cabochons, beads, ornamental objects, and lapidary work; durable pieces may be polished as decorative stone.
Geological facts
Carnelian is orange-red chalcedony, while jasper is more opaque and commonly includes impurities. The image may show a transitional or mixed specimen rather than a definitive gem variety.
Field identification & locations
Identify by its glassy-to-waxy appearance, conchoidal fracture, lack of cleavage, and inability to scratch it with a steel knife; quartz should scratch glass. Common sources include Brazil, India, Madagascar, Uruguay, and the western United States.
