gemstone
White Opal
Hydrated amorphous silica (SiO2·nH2O)
AI-generated identification · may be incorrectMohs hardness of 5.5-6.5, milky white color with subtle play-of-color, subvitreous to resinous luster, and amorphous crystal structure.
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Physical properties
Mohs hardness of 5.5-6.5, milky white color with subtle play-of-color, subvitreous to resinous luster, and amorphous crystal structure.
Formation & geological history
Formed from silica-rich solutions seeping into cracks and voids in sedimentary or volcanic rock over millions of years.
Uses & applications
Widely used in fine jewelry, carving, and as a collectible gemstone.
Geological facts
Opal contains up to 20% water trapped within its microscopic silica spheres, which diffract light to produce its characteristic iridescence.
Field identification & locations
Identified by its distinctive pale body tone, lightweight feel, and lack of cleavage; primarily sourced from Australia and Ethiopia.
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