Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Sonoran Sunset Jasper
A vivid copper-bearing Mexican stone of red cuprite and green chrysocolla that evokes a desert sunset.
mineral
Oregon Opal
Opal from Oregon, USA, ranging from translucent blue Owyhee opal to clear and fiery contra-luz precious opal from Opal Butte.
gemstone
Common Opal
Opal without play-of-color, valued for solid body hues; also called potch, it occurs in a wide range of colors worldwide.
gemstone
Red Opal
An opal with a deep red body color, often a variety of Mexican fire opal, prized for its warm, glowing intensity.
gemstoneSemiblack Opal
Opal with a dark grey body tone sitting between black and light opal, giving play-of-color rich contrast at an accessible price.
gemstone
Fossil Opal
Fossil material whose original substance has been replaced by opal, preserving ancient shapes in common or play-of-color opal.
gemstone
Slovakian Opal
Historic precious opal from the Dubnik mines of Slovakia, the famous source of European "Hungarian" opal for centuries.
gemstone
Cherry Opal
A translucent red opal, closely related to Mexican fire opal, glowing with a warm cherry-red body color often free of play-of-color.
gemstone
Fire Opal
A translucent to transparent opal in warm yellow, orange, and red tones, prized for body color rather than play-of-color.
gemstone
Velvet Opal
Opal with a soft, velvety surface sheen rather than sharp play-of-color, prized for its gentle glow.
gemstone
Bone Opal
Fossil bone in which opal has replaced the original tissue, sometimes showing play-of-color, a rare collector fossil.
gemstone
Cacholong Opal
An opaque, porcelain-white common opal prized for its milky, pearl-like appearance and high porosity, often carved or beaded.
gemstone
Menilite Opal
An opaque grey-brown common opal forming nodules and concretions, historically called liver opal for its dull brownish color.
mineral
Crystal Opal
Precious opal with a transparent or translucent body, letting play-of-color glow with exceptional depth and clarity.
gemstone
Pinfire Opal
A precious opal pattern made of tiny, densely packed pinpoint flashes of play-of-color, like sparkling speckles across the stone.
gemstoneSatin Opal
Opal showing a smooth, silky satin-like sheen across its surface, valued for a gentle, refined luster.
gemstonePeruvian Blue Opal
A translucent common opal from the Andes prized for its serene blue to blue-green color, usually cut into cabochons and beads.
gemstone
Green Opal
A common opal colored green by nickel or chromium impurities, usually opaque and cut into cabochons and beads.
gemstone
Brazilian Opal
Precious opal from Brazil, especially the Pedro II area of Piaui, known for bright, often stable crystal and white opal.
gemstoneWhite Cliffs Opal
Precious opal from the historic White Cliffs field in New South Wales, Australia, famous for light opal and rare opal pineapples.
gemstone
Lightning Ridge Opal
Opal from Lightning Ridge, Australia, the world's premier source of black opal with brilliant color on a dark body.
gemstone
Leopard Opal
A patterned common opal with mottled, leopard-like spots and blotches, prized as an ornamental and cabochon stone.
gemstone
Sideromelane
A transparent, pale brown basaltic volcanic glass formed when basalt lava is quenched extremely fast, often underwater.
igneous
Boulder Opal
Precious opal that forms in thin veins within brown ironstone boulders, cut with the host rock left as a natural dark backing.
gemstone