Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Goldstone
A man-made glittering glass packed with tiny copper crystals, traditionally reddish-brown but also made in blue and green.
crystalLuxullianite
A distinctive tourmaline-rich granite from Cornwall, prized as an ornamental stone for its pink feldspar set with radiating black tourmaline.
igneousMint Garnet
A delicate pastel-green grossular garnet, lighter than tsavorite, most famously from the Merelani Hills of Tanzania.
gemstone
Brandberg Amethyst
A prized Namibian quartz combining amethyst, smoky, and clear quartz in single crystals, often with phantoms and enhydros.
crystal
Cathedral Quartz
Quartz with a stepped, multi-pointed structure of parallel side crystals resembling the spires of a cathedral.
crystal
Verdite
A rich green, fuchsite-rich metamorphic rock from southern Africa, prized as a carving and ornamental stone.
metamorphic
Faden Quartz
Tabular quartz crossed by a milky white thread-like line marking where the crystal repeatedly cracked and re-healed.
crystal
Glauconite
A soft, green iron-potassium mica that forms in marine sediments and gives greensand its characteristic olive color.
mineral
Lithium Quartz
A quartz crystal containing pink to lilac lithium-bearing mineral inclusions that give a soft cloudy lavender or rose coloration.
crystal
Andamooka Opal
Precious opal from the Andamooka field of South Australia, famous for solid crystal opal and its distinctive treatable matrix opal.
gemstone
Peacock Opal
A precious opal showing dominant peacock-like blue, green and teal play-of-color, often on Ethiopian material.
gemstone
Herkimer Diamond
Exceptionally clear, naturally double-terminated quartz crystals from Herkimer County, New York, prized for their diamond-like brilliance.
crystal
Chrysoprase
A translucent apple-green chalcedony colored by nickel, the most prized green variety of the quartz family.
gemstone
Aquamarine
The serene blue-to-sea-green variety of beryl, aquamarine is a durable gemstone colored by trace iron and birthstone for March.
gemstone
Chlorite Schist
A soft, green, foliated rock rich in chlorite, formed by low-grade metamorphism of mafic or volcanic rocks.
metamorphic
Strawberry Quartz
A pink-to-red quartz colored by iron oxide inclusions that create a speckled, strawberry-like appearance within clear crystal.
crystalGooseberry Garnet
Gooseberry Garnet is a soft green grossular garnet named for its resemblance to the pale, translucent green of ripe gooseberries.
gemstone
Merelani Mint Garnet
A delicate vanadium-colored mint-green grossular garnet from the Merelani Hills of Tanzania, the source of tanzanite.
gemstoneTurquoise Obsidian
A vivid turquoise-blue glass sold as obsidian; this bright color is virtually always manufactured rather than natural volcanic glass.
igneous
Rutilated Quartz
Clear or smoky quartz threaded with golden to reddish needles of rutile, also poetically called Venus hair stone.
crystal
Amazonite
The blue-green gem variety of microcline feldspar, often mottled with white, prized as an affordable ornamental stone.
mineral
Greenschist
A green, foliated low-grade metamorphic rock colored by chlorite, actinolite, and epidote, marking the greenschist metamorphic facies.
metamorphic
Hornblende Schist
A dark, foliated schist rich in needle-like hornblende crystals, formed by metamorphism of mafic igneous rocks.
metamorphicWatermelon Obsidian
A pink-and-green bicolor glass sold as obsidian; the watermelon coloring is manufactured and does not occur in natural volcanic glass.
igneous