gemstone
Fire Opal
Hydrated amorphous silica (SiO2·nH2O)
AI-generated identification · may be incorrectHardness of 5.5 to 6.5 on the Mohs scale, vibrant orange-red color, vitreous to greasy luster, and amorphous crystal structure with conchoidal fracture.
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Physical properties
Hardness of 5.5 to 6.5 on the Mohs scale, vibrant orange-red color, vitreous to greasy luster, and amorphous crystal structure with conchoidal fracture.
Formation & geological history
Forms in hydrothermal veins or near volcanic hot springs when silica-rich groundwater fills cavities at low temperatures.
Uses & applications
Primarily cut into faceted gemstones or cabochons for fine jewelry and prized by mineral collectors.
Geological facts
Unlike precious opal, fire opal is often valued for its intense body color rather than a play of color, though some specimens exhibit both.
Field identification & locations
Identified by its warm, fiery orange color and conchoidal fracture, commonly sourced from Mexico and parts of the western United States.
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