Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Iceland Spar
A transparent, optical-grade variety of calcite famous for strong double refraction, splitting images and light into two rays.
mineral
Lepidolite
A soft lithium-bearing mica with a lilac to purple color and pearly, flaky sheen, an important ore of lithium.
mineral
Grape Agate
Clusters of tiny botryoidal chalcedony spheres resembling bunches of grapes, famously purple, found in Indonesia.
mineral
Calcite
An extremely common calcium carbonate mineral that comes in nearly every color and shows strong double refraction in clear crystals.
mineral
Halite
The natural mineral form of table salt, a soft, water-soluble evaporite that forms perfect cubic crystals and tastes salty.
mineral
Brazilian Opal
Precious opal from Brazil, especially the Pedro II area of Piaui, known for bright, often stable crystal and white opal.
gemstone
Purple Tourmaline
An uncommon purple to violet tourmaline colored by manganese, the deeper reddish-purple stones sometimes called siberite.
gemstone
Needle Tourmaline
Fine acicular (needle-like) tourmaline crystals, often black schorl, frequently seen as slender inclusions within clear quartz.
mineral
Prasiolite
A pale green variety of quartz, usually created by heat-treating amethyst, often marketed as green amethyst.
gemstoneGondite
A metamorphic rock made chiefly of manganese-rich spessartine garnet and quartz, formed from ancient manganese-bearing sediments.
metamorphic
Danburite
A glassy calcium borosilicate forming wedge-tipped prismatic crystals, usually colorless to pale yellow or pink, sometimes faceted as a gem.
crystal
Chevron Amethyst
A naturally banded quartz combining purple amethyst and white quartz in striking V-shaped chevron or zigzag patterns.
crystalMalaia Garnet
A pyrope-spessartine garnet in warm peach, salmon, and pinkish-orange tones, originally rejected by dealers and named 'malaia,' Swahili for outcast.
gemstone
Botswana Agate
A finely banded agate from Botswana known for delicate parallel layers of grey, pink, and white.
mineralLotus Garnet
A delicate pinkish-purple to peach garnet from Tanzania, a pyrope-spessartine blend named for the soft colors of a lotus flower.
gemstone
Raspberry Garnet
A vivid pinkish-red rhodolite garnet named for its raspberry color, a bright pyrope-almandine blend popular in jewelry.
gemstone
Andamooka Opal
Precious opal from the Andamooka field of South Australia, famous for solid crystal opal and its distinctive treatable matrix opal.
gemstone
Mariposite
A green, gold-associated metamorphic rock made of chrome-rich mica and quartz, named for Mariposa County in California's gold country.
metamorphic
Vorobyevite
An old name for cesium-rich, often pink beryl (related to morganite), named after Russian mineralogist Victor Vorobyev.
gemstone
Cherry Opal
A translucent red opal, closely related to Mexican fire opal, glowing with a warm cherry-red body color often free of play-of-color.
gemstone
Latite
The fine-grained volcanic equivalent of monzonite, an intermediate lava with nearly equal feldspars and little free quartz.
igneous
Carnelian
A warm orange-to-red variety of chalcedony quartz colored by iron oxide, used since antiquity for seals, beads, and cabochons.
gemstone
Quartzite
An extremely hard metamorphic rock formed from sandstone, made of fused quartz grains that break across rather than between the grains.
metamorphicMahenge Garnet
Mahenge Garnet is a pyrope-spessartine gem from Tanzania's Mahenge region, prized for vivid pink, purple, and color-change tones.
gemstone