Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Spectrolite
A premium dark Finnish labradorite displaying the full color spectrum of iridescent flashes, prized as one of the most vivid feldspar gems.
gemstone
Neon Blue Tourmaline
An intensely glowing copper-bearing tourmaline whose electric neon-blue color makes it one of the most valuable gems in the world.
gemstone
Red Beryl
An exceptionally rare red variety of beryl colored by manganese, found chiefly in Utah and prized as one of the rarest gems.
gemstone
Adularia
A low-temperature potassium feldspar famous for forming transparent Alpine crystals and the gem moonstone, which shows a floating blue sheen called adularescence.
mineral
Copper-Bearing Tourmaline
Tourmaline colored by copper, producing the famous vivid neon blues, greens and teals known commercially as Paraiba-type gems.
gemstone
Bytownite
A calcium-rich plagioclase feldspar between labradorite and anorthite, faceted as transparent golden-yellow gems sometimes sold as yellow labradorite.
gemstone
Mozambique Garnet
An abundant, brightly colored pyrope-almandine garnet from East Africa, valued for its clean, raspberry-to-red gems at accessible prices.
gemstone
Komatiite
A rare, ancient ultramafic volcanic rock formed from extremely hot magma, famous for its spinifex texture.
igneous
Jelly Opal
A translucent, gelatinous-looking opal whose transparency gives floating, glowing play-of-color a watery, jelly-like appearance.
gemstone
Sugilite
A rare deep-purple manganese-bearing silicate, mostly from South Africa, prized for its vivid violet color.
mineral
Green Obsidian
Green-tinted volcanic glass; some is naturally colored by trace iron, but vivid emerald-green pieces are usually manufactured glass.
crystal
Green Tourmaline
The green variety of tourmaline, also called verdelite, ranging from bright grass green to deep forest tones colored by iron.
gemstone
Serpentine
A group of green magnesium silicate minerals with a smooth, waxy feel, often carved and sometimes sold as imitation jade.
mineral
Green Jasper
An opaque green variety of chalcedony quartz colored by iron and chlorite-group inclusions, prized as a durable carving and cabochon stone.
mineral
Mustard Tourmaline
A warm mustard to brownish-yellow tourmaline, colored by iron or manganese, sitting between yellow and brown dravite tones.
gemstone
Green Sheen Obsidian
Black volcanic glass that flashes a green sheen at certain angles due to light interference off aligned microscopic inclusions.
igneous
Pyroxenite
A dense, dark ultramafic plutonic rock composed almost entirely of pyroxene minerals, often associated with peridotite and layered intrusions.
igneous
Malachite
A vivid green copper carbonate mineral famous for swirling concentric bands, used as an ore of copper and an ornamental gemstone.
mineral
Fairburn Agate
The state gemstone of South Dakota, a rare fortification agate known for tight, holly-leaf concentric banding.
gemstone
Glauconite
A soft, green iron-potassium mica that forms in marine sediments and gives greensand its characteristic olive color.
mineral
Topaz
A hard, brilliant fluorosilicate gemstone occurring in many colors, from precious golden imperial topaz to popular blue topaz.
gemstone
Smoky Quartz
The smoky brown to gray variety of quartz, colored by natural irradiation, valued as both a gemstone and crystal specimen.
crystal
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
Aquamarine
The serene blue-to-sea-green variety of beryl, aquamarine is a durable gemstone colored by trace iron and birthstone for March.
gemstone