mineral
White Opal
Hydrated Silica (SiO2·nH2O)
AI-generated identification · may be incorrectHardness of 5.5-6.5 on the Mohs scale, milky white color with occasional play-of-color, vitreous to sub-resinous luster, and amorphous crystal structure.
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Physical properties
Hardness of 5.5-6.5 on the Mohs scale, milky white color with occasional play-of-color, vitreous to sub-resinous luster, and amorphous crystal structure.
Formation & geological history
Formed at low temperatures from silica-rich groundwater depositing in voids of sedimentary or volcanic rocks.
Uses & applications
Used primarily in jewelry making, ornamental carvings, and as collector specimens.
Geological facts
Opal contains up to 21% water within its microscopic silica spheres, which diffract light to create its signature iridescence.
Field identification & locations
Identified by its conchoidal fracture, waxy luster, and lack of cleavage; commonly mined in Australia and Ethiopia.
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Sandstone (with potential mineral staining/concretions)
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Pegmatite with Tourmaline and Quartz
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Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Granite
Granite (Phaneritic intrusive igneous rock)
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