Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
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
Cinnamon Stone
The warm cinnamon-to-honey-brown variety of grossular garnet, also known as hessonite, with a characteristic swirly internal texture.
gemstone
Jet
A lightweight black organic gemstone formed from fossilized wood under pressure, a type of lignite long used in mourning jewelry.
sedimentary
Morganite
The pink-to-peach variety of beryl colored by manganese, popular for romantic engagement jewelry.
gemstone
Goshenite
The colorless variety of beryl, named after Goshen, Massachusetts, prized for its purity, clarity, and durability.
gemstone
White Topaz
A colorless, transparent variety of topaz valued as an affordable, hard, brilliant alternative to diamond in jewelry.
gemstone
Blue Chalcedony
A translucent, soft blue variety of microcrystalline quartz whose color comes from light scattering through its fine structure.
mineral
Lodestone
A naturally magnetized variety of magnetite that attracts iron, historically used as the first magnetic compass.
mineral
Jasper
An opaque, often colorfully patterned variety of chalcedony quartz, popular for tumbling, carving, and jewelry.
mineral
Prasiolite
A pale green variety of quartz, usually created by heat-treating amethyst, often marketed as green amethyst.
gemstone
Iolite
The gem variety of cordierite, famous for strong pleochroism that shifts from violet-blue to near-colorless.
gemstone
Green Quartz
A green variety of macrocrystalline quartz, usually the heat- or radiation-altered prasiolite, prized for its soft mint hue.
crystal
Goshenite Crystal
The pure colorless variety of beryl, valued as crystal specimens and as a brilliant alternative to clearer gemstones.
crystal
Cranberry Tourmaline
A deep cranberry-red to purplish-pink variety of lithium-rich elbaite tourmaline, prized as a rich, saturated rubellite gemstone.
gemstone
Achroite
The rare colorless variety of tourmaline, named from the Greek for 'without color' and prized by collectors.
gemstone
Black Tourmaline
The opaque black iron-rich variety of tourmaline (schorl), forming striated prismatic crystals popular as a protective grounding stone.
mineral
Orange Garnet
A trade term for orange garnets, mainly manganese-rich spessartine and the brownish hessonite variety of grossular.
gemstone
Chrysoprase
A translucent apple-green chalcedony colored by nickel, the most prized green variety of the quartz family.
gemstone
Onyx
A banded variety of chalcedony quartz, classically black or black-and-white, long favored for cameos and beads.
gemstone
Mint Tourmaline
A soft, pastel minty-green tourmaline prized for its fresh, light color, a delicate variety of green elbaite.
gemstone
Golden Beryl
The pure golden-yellow gem variety of beryl, colored by iron and valued for its clarity, brilliance, and durability.
gemstone
Emerald Crystal
The natural crystalline form of emerald, the prized green chromium-and-vanadium variety of beryl and the May birthstone.
crystal
Emerald Green Tourmaline
A richly saturated green variety of elbaite tourmaline whose color rivals emerald, colored by trace iron, chromium, or vanadium.
gemstone
Agate
A banded variety of chalcedony quartz, famed for its colorful concentric layers and enormous range of patterns and colors.
mineral