gemstone
Fire Opal
Hydrated amorphous silica (SiO2·nH2O)
AI-generated identification · may be incorrectHardness of 5.5-6.5 on the Mohs scale, warm orange to yellow-brown color, vitreous to greasy luster, and amorphous crystal structure.
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Physical properties
Hardness of 5.5-6.5 on the Mohs scale, warm orange to yellow-brown color, vitreous to greasy luster, and amorphous crystal structure.
Formation & geological history
Formed from silica-rich water solutions filling fissures in volcanic rock at shallow depths, typically during the Tertiary period.
Uses & applications
Primarily cut into faceted or cabochon gemstones for jewelry and highly sought after by mineral collectors.
Geological facts
Unlike precious opal, fire opal is prized for its intense body color rather than play-of-color, though exceptional specimens can exhibit both.
Field identification & locations
Identified by its distinctive warm translucent colors and conchoidal fracture, commonly sourced from Mexico and volcanic regions worldwide.
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