Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Dark Green Tourmaline
Deeply saturated green tourmaline colored by iron, often so dark it appears nearly black until viewed in bright light.
gemstoneOrange Obsidian
Obsidian colored orange by iron oxide inclusions; vivid uniform orange material is frequently manufactured glass rather than volcanic.
igneousPrase
An old name for a dull leek-green variety of quartz or chalcedony colored by green mineral inclusions, historically called mother of emerald.
crystal
Bixbite
An old trade name for red beryl, the extremely rare manganese-colored beryl from Utah, now largely replaced by the term red beryl.
gemstone
Verdelite
The classic green gem variety of elbaite tourmaline, ranging from bright grass-green to deep forest tones colored by iron or chromium.
gemstone
Pumpkin Obsidian
An orange-to-rust colored variety of natural volcanic glass whose warm tone comes from iron oxide staining within the obsidian.
igneousBekily Garnet
A rare color-change garnet from Bekily, Madagascar, shifting from bluish-green in daylight to purplish-red under warm light, including the famed blue garnets.
gemstone
Lindi Garnet
Lindi Garnet is a rare vanadium-rich color-change garnet from Tanzania's Lindi region, shifting from blue-green daylight tones to purple-red.
gemstone
Watermelon Tourmaline
A striking color-zoned tourmaline with a pink center and green rind, resembling a slice of watermelon when cut across the crystal.
gemstone
Rainbow Tourmaline
Tourmaline showing many color zones in a single crystal, often revealing spectacular concentric patterns when sliced.
gemstone
Alexandrite
A rare color-change chrysoberyl that appears green in daylight and red under incandescent light, sometimes called emerald by day, ruby by night.
gemstone
Flash Opal
A precious opal whose play-of-color appears as broad rolling flashes of spectral color that shift as the stone moves.
gemstoneMasasi Blue Garnet
Masasi Blue Garnet is a rare vanadium-bearing color-change garnet from Tanzania that appears blue-green by day and purplish-red indoors.
gemstone
Amazonite
The blue-green gem variety of microcline feldspar, often mottled with white, prized as an affordable ornamental stone.
mineralMalaia Garnet
A pyrope-spessartine garnet in warm peach, salmon, and pinkish-orange tones, originally rejected by dealers and named 'malaia,' Swahili for outcast.
gemstone
Precious Opal
The classic gem opal that flashes shifting spectral colors, defined by the diffraction effect known as play-of-color.
gemstoneMahenge Garnet
Mahenge Garnet is a pyrope-spessartine gem from Tanzania's Mahenge region, prized for vivid pink, purple, and color-change tones.
gemstone
Black Opal
The rarest and most valuable opal, with a dark body tone that makes its flashing rainbow play-of-color blaze brilliantly.
gemstone
Peach Tourmaline
A gentle peachy-pink tourmaline blending soft pink and orange tones, a delicate pastel variety of elbaite.
gemstoneIridescent Obsidian
A black volcanic glass that displays shifting rainbow or metallic sheen from microscopic nanoparticle layers trapped inside.
igneous
Rainbow Opal
Precious opal that displays a broad, vivid sweep of spectral colors, flashing the full rainbow as it is tilted in the light.
gemstone
Nevada Opal
Opal mined in Nevada, famous for fiery black precious opal and opalized wood from the Virgin Valley district.
gemstoneContra-Luz Opal
A rare opal whose play-of-color appears only when light passes through it, glowing best when backlit or held to the light.
gemstone
Maxixe Aquamarine
A deep blue beryl whose intense color comes from radiation-induced color centers and tends to fade in light, named after the Maxixe mine in Brazil.
gemstone