gemstone
Blue Topaz
Aluminum silicate fluoride hydroxide, Al2SiO4(F,OH)2
AI-generated identification · may be incorrectHardness of 8 on the Mohs scale, vitreous luster, orthorhombic crystal system, and perfect basal cleavage. Color is bright blue, often achieved via irradiation and heat treatment of colorless natural topaz.
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Physical properties
Hardness of 8 on the Mohs scale, vitreous luster, orthorhombic crystal system, and perfect basal cleavage. Color is bright blue, often achieved via irradiation and heat treatment of colorless natural topaz.
Formation & geological history
Forms in pegmatites, high-temperature quartz veins, and cavities in rhyolite and granite igneous rocks through pneumatolytic processes.
Uses & applications
Widely used in fine jewelry, rings, pendants, and as a birthstone for December.
Geological facts
Natural deep blue topaz is extremely rare; most commercial blue topaz is treated from colorless stones using modern irradiation techniques.
Field identification & locations
Identified by its distinct high hardness, vitreous luster, and specific gravity around 3.5. Found globally including Brazil, Sri Lanka, and Nigeria.
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