Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Alexandrite
A rare color-change chrysoberyl that appears green in daylight and red under incandescent light, sometimes called emerald by day, ruby by night.
gemstonePearl
An organic gem formed inside mollusks from layered nacre, prized for its iridescent luster and classic elegance.
gemstoneMaligano Jasper
A rare Indonesian jasper from Sulawesi known for ghostly tube structures, brecciated patterns, and contrasting grey, red, and purple zones.
mineral
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
Opal
A hydrated silica gemstone famous for its shimmering play-of-color, ranging from white and black opal to fiery orange fire opal.
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
Ametrine
A natural bicolor quartz that combines purple amethyst and golden citrine in a single crystal.
crystal
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
Flower Agate
A creamy pink-and-white chalcedony from Madagascar containing flower-like plume inclusions that resemble blossoms suspended in stone.
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.
gemstonePipestone
A soft, fine-grained red metamorphosed claystone, sacred to many Native American peoples and carved into ceremonial pipes.
metamorphic
Cat's Eye Tourmaline
Tourmaline displaying chatoyancy, a moving band of light caused by parallel tube-like inclusions, when cut as a cabochon.
gemstoneCat's Eye Morganite
Pink beryl (morganite) that shows chatoyancy, a moving band of light, when cut as a cabochon, thanks to parallel tube inclusions.
gemstone
Cat's Eye Beryl
Beryl displaying chatoyancy, a bright moving band of light, caused by parallel tube-like inclusions when cut as a cabochon.
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