Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Star Garnet
A rare almandine garnet that displays a four- or six-rayed star (asterism) from oriented rutile inclusions; the state gem of Idaho.
gemstone
Demantoid Garnet
A rare green andradite garnet famed for fire exceeding diamond and distinctive horsetail inclusions in Russian stones.
gemstone
Tangerine Quartz
Clear quartz coated with orange-red hematite, giving points a vivid tangerine color, mainly from Brazil.
crystal
Rhodolite Garnet
A purplish-red to raspberry garnet that is a natural blend of pyrope and almandine, prized for its bright rose-violet color.
gemstone
Black Garnet
An opaque black garnet — typically titanium-bearing melanite andradite — historically cut for mourning and Victorian jewelry.
gemstoneLeuco Garnet
The rare colorless variety of grossular garnet, a near-flawless transparent gem free of the iron and chromium that color most garnets.
gemstone
Color Change Garnet
A rare garnet that dramatically shifts color from greenish in daylight to reddish under lamplight, rivaling alexandrite.
gemstone
Strawberry Quartz
A pink-to-red quartz colored by iron oxide inclusions that create a speckled, strawberry-like appearance within clear crystal.
crystalMasasi Blue Garnet
Masasi Blue Garnet is a rare vanadium-bearing color-change garnet from Tanzania that appears blue-green by day and purplish-red indoors.
gemstone
Golden Healer Quartz
Quartz colored or coated by golden iron oxides such as limonite or goethite, giving a warm sunlit yellow glow.
crystalGondite
A metamorphic rock made chiefly of manganese-rich spessartine garnet and quartz, formed from ancient manganese-bearing sediments.
metamorphic
Calderite
A manganese-iron garnet that forms in metamorphosed manganese deposits, intermediate in composition between spessartine and andradite.
mineralEltyubyuite
A rare chlorine-bearing iron garnet-supergroup mineral, the ferric analogue of wadalite, formed in high-temperature combustion-metamorphic rocks.
mineralRed Sandstone
Iron-stained sandstone whose red color comes from hematite coatings, formed in oxidizing desert, river, and coastal environments.
sedimentary
Garden Quartz
Clear quartz filled with mineral inclusions that look like underwater gardens, mossy landscapes, or floating scenery.
crystal
Khondalite
A high-grade metamorphic gneiss of garnet, sillimanite, quartz, and graphite, derived from ancient aluminous sediments.
metamorphicMorimotoite
A black titanium garnet related to andradite and schorlomite, containing tetravalent titanium and ferrous iron, found in skarns and alkaline rocks.
mineral
Brown Jasper
An opaque earth-toned jasper colored brown by iron oxides, ranging from pale tan to deep chocolate.
mineral
Red Jasper
An opaque, iron-rich variety of microcrystalline quartz known for its deep brick-red color and ancient history as a stone of strength and grounding.
gemstone
Itabirite
A metamorphosed banded iron formation of alternating quartz and iron-oxide layers, mined as a major iron ore.
metamorphic
Kyanite Schist
A mica schist containing bladed blue kyanite crystals, a marker of medium- to high-grade metamorphism of aluminous rocks.
metamorphic
Mahogany Obsidian
A natural volcanic glass with rich brown and black mahogany-like swirls created by iron oxide inclusions.
igneousHydroandradite
A hydrous, iron-rich garnet of the hydrogarnet group in which hydroxyl groups substitute for silica within the andradite structure.
mineral
Amethyst
The purple variety of quartz, colored by iron and natural irradiation, prized as the classic violet birthstone of February.
crystal