Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Orbicular Granite
A rare granitic rock containing concentric, onion-like spheres called orbicules, prized as a striking ornamental stone.
igneous
Vanadinite
A brilliant orange-red lead vanadate mineral forming hexagonal crystals, prized by collectors and mined as an ore of vanadium.
mineralDallasite Jasper
A green-and-white volcanic breccia from Vancouver Island, cemented by jasper and rich in epidote, popular as a regional lapidary stone.
gemstone
Diamond
The hardest known natural material, a crystalline form of pure carbon prized as the ultimate gemstone for its brilliance and fire.
gemstone
Needle Tourmaline
Fine acicular (needle-like) tourmaline crystals, often black schorl, frequently seen as slender inclusions within clear quartz.
mineralTurquoise Obsidian
A vivid turquoise-blue glass sold as obsidian; this bright color is virtually always manufactured rather than natural volcanic glass.
igneous
Cranberry Tourmaline
A deep cranberry-red to purplish-pink variety of lithium-rich elbaite tourmaline, prized as a rich, saturated rubellite gemstone.
gemstone
Blue Quartz
A naturally blue quartz colored by tiny mineral inclusions such as dumortierite or scattered rutile and tourmaline fibers.
crystalTripolite
A soft, lightweight siliceous sedimentary rock made of fossil diatom remains, prized as a fine natural abrasive and polishing powder.
sedimentary
Copper-Bearing Tourmaline
Tourmaline colored by copper, producing the famous vivid neon blues, greens and teals known commercially as Paraiba-type gems.
gemstone
Leopard Skin Jasper
A spotted jasper-rhyolite patterned with leopard-like rings and ovals, valued as an earthy ornamental and lapidary stone.
sedimentary
Pink Beryl
The pink to peach variety of beryl, better known as morganite, colored by manganese and prized for its gentle pastel hues.
gemstone
Rosolite Garnet
A rose-pink variety of grossular garnet from Mexico, also known as landerite or xalostocite, prized for its soft pink color.
gemstone
Ruby
The red, chromium-colored variety of corundum, prized as one of the most valuable colored gemstones and second only to diamond in hardness.
gemstone
Cat's Eye Tourmaline
Tourmaline displaying chatoyancy, a moving band of light caused by parallel tube-like inclusions, when cut as a cabochon.
gemstone
Pineapple Opal
A rare opal pseudomorph from White Cliffs, Australia, formed as opal replaced clustered crystals into a pineapple-like shape.
gemstone
Red Tourmaline
Vivid red to raspberry tourmaline, the most intense colors are marketed as rubellite, colored by manganese in the elbaite structure.
gemstone
Black Tourmaline
The opaque black iron-rich variety of tourmaline (schorl), forming striated prismatic crystals popular as a protective grounding stone.
mineralWatermelon Obsidian
A pink-and-green bicolor glass sold as obsidian; the watermelon coloring is manufactured and does not occur in natural volcanic glass.
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
Euxenite
A black rare-earth niobium-tantalum oxide, often radioactive and metamict, mined for yttrium, niobium, and associated rare elements.
mineral
Peacock Ore
A copper-iron sulfide ore famous for its iridescent peacock-like purple and blue tarnish; often sold as treated chalcopyrite.
mineral
Yellow-Green Obsidian
A chartreuse yellow-green glass sold as obsidian; the bright color is manufactured and does not occur in natural volcanic glass.
igneousLavender Obsidian
A soft lavender-purple glass sold as obsidian; uniform lavender material is essentially always manufactured glass, not natural volcanic obsidian.
igneous