Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Rose Tourmaline
A soft to medium pink elbaite tourmaline in rose hues, colored by manganese and prized for romantic jewelry.
gemstone
Sapphire
The gem variety of corundum in every color except red, most prized in velvety blue and exceptionally hard and durable.
gemstone
Fire Opal
A translucent to transparent opal in warm yellow, orange, and red tones, prized for body color rather than play-of-color.
gemstone
Green Opal
A common opal colored green by nickel or chromium impurities, usually opaque and cut into cabochons and beads.
gemstoneCarrasite Jasper
An orbicular Madagascar jasper related to ocean jasper, showing eyes and swirls in cream, green, and earthy tones.
mineral
Paracelsian
A rare barium aluminosilicate that is a monoclinic polymorph of celsian, found in barium-rich metamorphic and manganese deposits.
mineral
Spinel
A durable magnesium aluminum oxide gem that occurs in many colors and was long mistaken for ruby.
gemstone
Sapropel
A soft, dark, organic-rich mud deposited in stagnant, oxygen-poor water, a key precursor to oil and gas source rocks.
sedimentary
Nephrite
One of the two jade minerals, an amphibole prized for its extreme toughness and soft, waxy green hues used in carving for millennia.
gemstone
Feruvite
A calcium- and ferrous-iron-rich tourmaline, the iron analogue of uvite, forming dark brown to black crystals in skarns and metamorphic rocks.
mineral
Violet Tourmaline
Elbaite tourmaline in violet to purple hues colored by manganese, a relatively scarce and sought-after tourmaline color.
gemstone
Siltstone
A fine-grained clastic rock of silt-sized grains, intermediate between sandstone and mudstone, with a gritty feel.
sedimentary
Gray Obsidian
Obsidian in gray tones, often semi-translucent, colored by light scattering and minor inclusions within the volcanic glass.
igneous
Smithsonite
Smithsonite is a zinc carbonate ore famous for glassy botryoidal crusts in blue-green, pink, and yellow hues.
mineralExotica Jasper
Also called Sci-Fi Jasper, a Mexican jasper-rhyolite with swirling abstract patterns in cream, tan, gray, pink, and green.
gemstone
Rossmanite
A rare lithium-aluminum tourmaline with a vacant X site, typically pale pink to colorless and found in lithium pegmatites.
mineral
Larimar
A rare sky-blue variety of pectolite found only in the Dominican Republic, prized for its sea-like color and white volcanic patterning.
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
Metagabbro
Coarse-grained gabbro that has been metamorphosed, partly recrystallizing into amphibole, plagioclase, and other metamorphic minerals.
metamorphic
Shonkinite
A dark, mafic potassic alkaline rock rich in augite with alkali feldspar and often nepheline, classically forming the base of layered sills.
igneous
Ijolite
A coarse-grained, feldspar-free plutonic rock composed mainly of nepheline and sodic pyroxene, the intrusive equivalent of nephelinite.
igneous
Goldstone
A man-made glittering glass packed with tiny copper crystals, traditionally reddish-brown but also made in blue and green.
crystal
Bubblegum Tourmaline
A bright, opaque-to-translucent bubblegum-pink elbaite tourmaline, a playful candy-pink variety popular in beads and cabochons.
gemstoneMintabie Opal
Precious opal from the Mintabie field in South Australia, known for hard, bright crystal opal and some dark-bodied stones.
gemstone