Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Graphic Granite
A pegmatitic granite in which quartz and feldspar intergrow to resemble ancient runic or Hebrew script.
igneous
Graphic Feldspar
A pegmatite rock of feldspar intergrown with wedge-shaped quartz that resembles ancient runic or Hebrew writing.
igneous
Color-Change Tourmaline
A rare tourmaline that visibly changes color between daylight and incandescent light, similar to the alexandrite effect.
gemstone
Cleavelandite
A striking platy, blade-like variety of albite feldspar that grows in fanned aggregates of thin white crystals within granite pegmatites.
mineral
Melanite Garnet
The titanium-rich black variety of andradite garnet, with a brilliant resinous luster prized for mourning and statement jewelry.
gemstone
Rubicline
An extremely rare rubidium-dominant alkali feldspar, the rubidium analogue of microcline, found in rare-element granitic pegmatites.
mineral
Black Garnet
An opaque black garnet — typically titanium-bearing melanite andradite — historically cut for mourning and Victorian jewelry.
gemstone
Hydrogrossular Garnet
A water-bearing massive grossular garnet, usually green or pink, widely used as a tough jade-like carving stone.
gemstone
Chrome Diopside
A vivid green chromium-bearing diopside, an affordable emerald-like gem mined largely in Siberia.
gemstone
Pelitic Schist
A schist derived from clay-rich sediments, rich in mica and often bearing index minerals like garnet, staurolite, or kyanite.
metamorphic
Lime Green Tourmaline
A bright, fresh lime to yellowish-green elbaite tourmaline (verdelite), colored by iron and trace manganese for a lively spring-green tone.
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
Teal Tourmaline
A sought-after elbaite tourmaline in teal hues that blend blue and green, prized for its ocean-like color.
gemstone
Purple-Pink Tourmaline
Elbaite tourmaline in purplish-pink to magenta hues, colored by manganese, prized for its vivid orchid-like tones.
gemstone
Trapiche Tourmaline
A rare tourmaline showing a fixed wheel-like pattern of color zones and arms radiating from the crystal's center.
gemstoneDendritic Jasper
A pale jasper threaded with black, fern-like mineral dendrites that mimic plants, trees, and frost despite being inorganic.
mineral
Cognac Tourmaline
A warm cognac-brown to reddish-brown tourmaline, typically magnesium-rich dravite, prized for its rich whisky-like color.
gemstoneParticolored Tourmaline
A tourmaline displaying two or more distinct colors in a single crystal, prized for natural color zoning like watermelon and bicolor stones.
gemstone
Mushroom Tourmaline
A rare mushroom-shaped tourmaline growth habit, typically magnesium-rich dravite/uvite, prized by collectors for its fungus-like cap-and-stem form.
mineral