mineral
Tumbled amber-colored chalcedony
Chalcedony (microcrystalline quartz, SiO₂), possibly yellow jasper or resinous amber-colored agate
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; mustard-yellow to honey-brown, translucent in places, with a waxy to dull luster and no visible cleavage. The triangular form appears shaped or naturally water-worn, with fine microcrystalline quartz texture; image alone cannot exclude dyed material or amber.
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Physical properties
Hardness about 6.5–7 Mohs; mustard-yellow to honey-brown, translucent in places, with a waxy to dull luster and no visible cleavage. The triangular form appears shaped or naturally water-worn, with fine microcrystalline quartz texture; image alone cannot exclude dyed material or amber.
Formation & geological history
Chalcedony forms when silica-rich groundwater fills cavities and fractures in volcanic or sedimentary rocks, commonly during the Cenozoic or older hydrothermal episodes. If true amber, it is fossilized tree resin and is much softer (2–2.5 Mohs), but the specimen’s granular appearance favors chalcedony/jasper.
Uses & applications
Used as lapidary material for cabochons, carvings, beads, ornaments, and decorative stone; industrial-grade chalcedony is a minor silica source.
Geological facts
The key distinction from amber is hardness: chalcedony resists scratching by steel, whereas amber scratches easily and may electrostatically attract paper after rubbing.
Field identification & locations
Common in volcanic cavities, silica-rich gravels, and locations such as Brazil, Uruguay, Mexico, India, and the western United States. Test cautiously with a steel point and observe translucency; avoid destructive tests on a collectible.
