Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Yellow-Green Obsidian
A chartreuse yellow-green glass sold as obsidian; the bright color is manufactured and does not occur in natural volcanic glass.
igneous
Neon Green Tourmaline
An intensely glowing green tourmaline, often copper-bearing, whose electric, almost luminous color recalls paraiba tourmaline.
gemstoneGary Green Jasper
An Oregon jasper, also called larsonite, of silicified fossil wood showing olive-green fields laced with black dendritic patterns.
mineral
Dark Green Tourmaline
Deeply saturated green tourmaline colored by iron, often so dark it appears nearly black until viewed in bright light.
gemstone
Forest Green Tourmaline
A deep, rich forest-green elbaite tourmaline (verdelite) colored mainly by iron, with strong pleochroism and excellent durability.
gemstoneStone Canyon Jasper
A warm-toned brecciated jasper from central California known for swirling browns, golds, and creams broken by darker seams.
gemstone
Cat's Eye Green Tourmaline
Green tourmaline cut as a cabochon to show a sharp moving band of light (chatoyancy) caused by fine parallel inclusions.
gemstone
Metaquartzite
A hard, tough metamorphic rock of fused quartz grains, formed by recrystallizing quartz sandstone under heat and pressure.
metamorphic
Itabirite
A metamorphosed banded iron formation of alternating quartz and iron-oxide layers, mined as a major iron ore.
metamorphic
Cherry Creek Jasper
A landscape-patterned Chinese jasper prized for warm cherry-red, cream, and green bands resembling painted scenery.
mineral
Banded Iron Formation
Ancient chemically deposited rock of alternating iron-oxide and silica bands recording Earth's early oxygenation and a major iron ore source.
sedimentary
Verdite
A rich green, fuchsite-rich metamorphic rock from southern Africa, prized as a carving and ornamental stone.
metamorphic
Metasandstone
Sandstone altered by metamorphism, with partly recrystallized quartz grains, transitional between true sandstone and quartzite.
metamorphic
Malachite
A vivid green copper carbonate mineral famous for swirling concentric bands, used as an ore of copper and an ornamental gemstone.
mineral
Bloodstone
A dark green chalcedony speckled with blood-red spots of iron oxide, traditionally known as heliotrope.
gemstoneHells Canyon Jasper
A warm earth-toned jasper from the Hells Canyon region of the Oregon-Idaho border, prized for brecciated browns, reds, and creams.
gemstone
Kentucky Agate
The official state rock of Kentucky, a banded agate famous for striking deep-red and black fortification patterns.
gemstone
Snow Quartz
An opaque, snow-white variety of quartz whose milky color comes from countless tiny gas and fluid inclusions.
crystal
Montana Moss Agate
A translucent chalcedony from Montana filled with black and red dendritic inclusions that look like moss, ferns, or scenic landscapes.
gemstoneMontana Garnet
Montana Garnet is red almandine recovered from Montana placer gravels, often alongside the state's famous sapphires.
gemstone
Bloodstone Jasper
A dark green jasper-chalcedony speckled with red iron-oxide spots, classically known as bloodstone or heliotrope.
mineral
Deschutes Jasper
A prized Oregon picture jasper from the Deschutes region known for soft scenic landscapes in cream, tan, and blue-gray.
mineral
Unakite
An altered granite mottled pink and green from feldspar and epidote, popular as a tough, colorful ornamental rock.
metamorphicDragon Blood Jasper
A green-and-red ornamental stone of epidote and red piemontite or iron oxide, named for its dragon-skin coloring; not a true jasper.
metamorphic