Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Australian Opal
Opal from Australia, the world's leading source of precious opal, ranging from white and crystal to prized black and boulder types.
gemstone
White Opal
The most common precious opal, with a pale milky body that shows softer pastel flashes of play-of-color throughout.
gemstoneFlame Opal
A glowing orange-to-red opal whose warm body color resembles flame; some stones add flashes of play-of-color.
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Blue Opal
A soft blue common opal, famously from Peru, valued for its serene sky-to-teal color rather than play-of-color.
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Spencer Opal
Precious opal from Spencer, Idaho, occurring in thin colorful seams that are typically cut into triplets.
gemstoneMorado Opal
Mexican purple common opal, "morado" meaning purple in Spanish, valued for its violet color and reputed UV color-shift.
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Orange Opal
A vivid orange opal, classically Mexican fire opal, prized for its bright, fiery body color that glows when backlit.
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Boulder Opal
Precious opal that forms in thin veins within brown ironstone boulders, cut with the host rock left as a natural dark backing.
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Flash Opal
A precious opal whose play-of-color appears as broad rolling flashes of spectral color that shift as the stone moves.
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Hyalite Opal
A clear, glassy, botryoidal common opal famous for its intense green fluorescence under UV light, caused by trace uranium.
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Nevada Opal
Opal mined in Nevada, famous for fiery black precious opal and opalized wood from the Virgin Valley district.
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Purple Opal
A purple-hued common opal, much of it the Mexican "morado" type, valued for even violet color rather than play-of-color.
gemstone
Lemon Opal
A bright lemon-yellow opal, usually common opal, valued for its cheerful citrus color and translucent glow.
gemstoneTintenbar Opal
Rare precious opal from Tintenbar in northern New South Wales, Australia, occurring in volcanic basalt rather than sedimentary rock.
gemstoneMint Opal
A soft mint-green variety of common opal, usually opaque and colored by trace copper or nontronite inclusions rather than play-of-color.
gemstoneGirasol Opal
A transparent to milky opal that displays a soft bluish-white internal glow or sheen that seems to follow the light source.
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Harlequin Opal
The rarest and most coveted opal play-of-color pattern, showing large, evenly spaced, angular mosaic patches of color.
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Andamooka Opal
Precious opal from the Andamooka field of South Australia, famous for solid crystal opal and its distinctive treatable matrix opal.
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Wood Opal
Fossil wood replaced by opaline silica that preserves wood grain, occasionally showing the play-of-color of precious opal.
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Dendritic Opal
A common opal with branching, tree-like mineral inclusions that create natural fern, moss, or landscape patterns.
gemstoneSunset Opal
An opal with warm sunset hues of orange, amber, and red, prized for its glowing fiery body color reminiscent of dusk skies.
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Oregon Opal
Opal from Oregon, USA, ranging from translucent blue Owyhee opal to clear and fiery contra-luz precious opal from Opal Butte.
gemstoneHoney Opal
A warm golden-to-amber opal ranging from translucent common opal to precious stones that flash play-of-color over a honey body.
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Common Opal
Opal without play-of-color, valued for solid body hues; also called potch, it occurs in a wide range of colors worldwide.
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