Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Green Calcite
A soft mint-to-apple-green variety of calcite, a common calcium carbonate mineral popular as soothing tumbled stones.
mineral
Calcite
An extremely common calcium carbonate mineral that comes in nearly every color and shows strong double refraction in clear crystals.
mineral
Emerald Crystal
The natural crystalline form of emerald, the prized green chromium-and-vanadium variety of beryl and the May birthstone.
crystal
Green Quartz
A green variety of macrocrystalline quartz, usually the heat- or radiation-altered prasiolite, prized for its soft mint hue.
crystal
Iceland Spar
A transparent, optical-grade variety of calcite famous for strong double refraction, splitting images and light into two rays.
mineral
Emerald in Matrix
Natural emerald crystals still embedded in their host rock, prized as mineral specimens that show how the gem grew in place.
gemstone
Geode
A hollow rock nodule whose interior cavity is lined with inward-pointing crystals such as quartz, amethyst, or calcite.
mineral
Marble
A metamorphosed limestone of interlocking calcite crystals, prized for sculpture and architecture for its workability and polish.
metamorphic
Cipollino Marble
A green-and-white banded metamorphic marble whose wavy mica layers resemble the rings of a sliced onion.
metamorphicAmegreen
A natural bicolor quartz blending amethyst purple with prasiolite green in a single crystal, prized as a metaphysical heart-crown stone.
crystal
Desert Rose
A rosette-shaped cluster of bladed gypsum or barite crystals that traps sand, forming flower-like formations in arid deserts.
mineral
Pyromorphite
A lead phosphate secondary mineral known for barrel-shaped green to yellow crystals formed in oxidized lead deposits.
mineral
Goldstone
A man-made glittering glass packed with tiny copper crystals, traditionally reddish-brown but also made in blue and green.
crystal
Uvarovite Garnet
The rare calcium-chromium garnet, famous for its sparkling emerald-green druzy crusts of tiny crystals, the only consistently green garnet.
mineral
Watermelon Tourmaline
A striking color-zoned tourmaline with a pink center and green rind, resembling a slice of watermelon when cut across the crystal.
gemstone
Hornblende Schist
A dark, foliated schist rich in needle-like hornblende crystals, formed by metamorphism of mafic igneous rocks.
metamorphic
Chrome-Dravite
A chromium-dominant tourmaline related to dravite, producing intensely deep green to blackish-green crystals from chromium-rich metamorphic rocks.
mineral
Ruby in Zoisite
A striking rock of green zoisite studded with red-pink ruby crystals and black hornblende, also called anyolite.
metamorphic
Uvite
A calcium-magnesium tourmaline that forms in metamorphosed limestones, typically dark green to brown and often in well-formed crystals.
mineralGrandite Garnet
Grandite is an intermediate garnet between grossular and andradite, common in skarns and prized for vivid green to golden crystals.
mineralMulticolor Tourmaline
Tourmaline crystals displaying two or more distinct colors at once, including the famous pink-and-green watermelon variety.
gemstone
Gahnite
A hard zinc-rich member of the spinel group, usually dark blue-green to black, forming octahedral crystals in metamorphic and pegmatitic rocks.
mineral
Selenite
A clear, soft crystalline variety of gypsum that forms glassy or fibrous wands, so soft it can be scratched with a fingernail.
crystal
Diamond
The hardest known natural material, a crystalline form of pure carbon prized as the ultimate gemstone for its brilliance and fire.
gemstone