Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Unakite
An altered granite mottled pink and green from feldspar and epidote, popular as a tough, colorful ornamental rock.
metamorphicUnakite Jasper
An altered granite of pink feldspar, green epidote and quartz, mottled pink-and-green and popular as a tumbled and carving stone.
metamorphic
Orbicular Granite
A rare granitic rock containing concentric, onion-like spheres called orbicules, prized as a striking ornamental stone.
igneous
Amphibolite
A dark, dense metamorphic rock dominated by hornblende and plagioclase, formed by medium- to high-grade metamorphism of basalt.
metamorphic
Charnockite
A granite-like rock containing orthopyroxene, formed at high temperatures and pressures and often classed with the granulites.
igneousLuxullianite
A distinctive tourmaline-rich granite from Cornwall, prized as an ornamental stone for its pink feldspar set with radiating black tourmaline.
igneous
Thulite
A pink, manganese-rich variety of zoisite used as an ornamental gemstone, often mottled with white quartz and grey matrix.
gemstone
Prehnite
A translucent yellow-green silicate famous for its botryoidal 'grape' clusters, often hosting needle-like sprays of black epidote.
mineral
Granodiorite
A common coarse-grained intrusive rock like granite but richer in plagioclase than potassium feldspar.
igneous
Calc-Silicate Rock
A metamorphic rock of calcium-rich silicate minerals formed from impure limestone or dolomite altered by heat and fluids.
metamorphic
Color Change Garnet
A rare garnet that dramatically shifts color from greenish in daylight to reddish under lamplight, rivaling alexandrite.
gemstone
Metabasalt
Basalt that has been metamorphosed, developing new minerals like chlorite, actinolite, and epidote that give it a greenish color.
metamorphic
Chrome Diopside
A vivid green chromium-bearing diopside, an affordable emerald-like gem mined largely in Siberia.
gemstone
Chrome Tourmaline
An intensely green tourmaline colored by chromium and vanadium, prized for its vivid emerald-like color from East Africa.
gemstone
Cleavelandite
A striking platy, blade-like variety of albite feldspar that grows in fanned aggregates of thin white crystals within granite pegmatites.
mineral
Rubellite
The red to raspberry-pink variety of tourmaline, prized for its vivid ruby-like color that holds under both daylight and artificial light.
gemstone
Hydrogrossular Garnet
A water-bearing massive grossular garnet, usually green or pink, widely used as a tough jade-like carving stone.
gemstone
Pelitic Schist
A schist derived from clay-rich sediments, rich in mica and often bearing index minerals like garnet, staurolite, or kyanite.
metamorphic
Graphite Schist
A dark, foliated schist rich in graphite that leaves a grey-black mark and forms from metamorphosed carbon-rich sediments.
metamorphic
Perlite
A hydrated volcanic glass with pearly, onion-like concentric cracks that pops into lightweight white granules when heated.
igneousDendritic Jasper
A pale jasper threaded with black, fern-like mineral dendrites that mimic plants, trees, and frost despite being inorganic.
mineral