Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Anglesite
A heavy lead sulfate secondary mineral, often colorless to white with adamantine luster, formed by the oxidation of galena.
mineral
Green Marble
A green ornamental stone, often serpentine-rich marble or verde antique, valued for its rich green color and white veining.
metamorphic
Acanthite
A silver sulfide that is one of the most important silver ore minerals, forming dark metallic crystals and wires.
mineral
Hyalophane
A barium-bearing potassium feldspar intermediate between orthoclase and celsian, found in barium-rich metamorphic and ore deposits.
mineral
Pyrolusite
A black manganese dioxide mineral that is the most important ore of manganese and a source of black pigment and dendrites.
mineral
Crocoite
A striking lead chromate mineral prized for its brilliant orange-red prismatic crystals, with the finest specimens from Tasmania.
mineral
Verdite
A rich green, fuchsite-rich metamorphic rock from southern Africa, prized as a carving and ornamental stone.
metamorphic
Siderite
Siderite is an iron carbonate ore, a brown rhombohedral mineral of the calcite group found in sediments and veins.
mineral
Oil Shale
A fine-grained sedimentary rock rich in solid organic matter (kerogen) that yields oil and gas when heated.
sedimentary
Azurite
A deep blue copper carbonate mineral that forms in oxidized copper deposits, often alongside green malachite.
mineral
Quartzite
An extremely hard metamorphic rock formed from sandstone, made of fused quartz grains that break across rather than between the grains.
metamorphic
Galena
A heavy, lead-grey metallic mineral with perfect cubic cleavage, galena is the world's main ore of lead and often carries silver.
mineral
Malachite
A vivid green copper carbonate mineral famous for swirling concentric bands, used as an ore of copper and an ornamental gemstone.
mineralPriday Plume Agate
A classic Oregon plume agate from the Priday Ranch beds, showing feathery mineral plumes suspended in translucent chalcedony.
gemstone
Pyromorphite
A lead phosphate secondary mineral known for barrel-shaped green to yellow crystals formed in oxidized lead deposits.
mineral
Bronzite
An iron-rich orthopyroxene prized for its warm bronze schiller, a metallic-looking sheen created by tiny mineral inclusions.
mineral
Aragonite
A calcium carbonate mineral and polymorph of calcite, aragonite forms distinctive needle clusters, sea shells, and pearls.
mineral
Skarn
A calc-silicate rock formed by chemical exchange between magma and carbonate rock, often rich in garnet and economically important ore minerals.
metamorphic
Potassium Feldspar
The potassium-rich feldspar group - orthoclase, microcline, and sanidine - a major rock-forming mineral often recognized by its salmon-pink color.
mineral
Talc-carbonate Rock
A soft metamorphic rock made of talc and magnesite or dolomite, formed by hydrothermal alteration of ultramafic rocks.
metamorphic
Flower Jasper
A jasper whose radiating mineral clusters form flower-like rosettes scattered across an earthy background.
mineral
Syenite
A coarse-grained intrusive igneous rock dominated by alkali feldspar with little or no quartz.
igneous
Garden Quartz
Clear quartz filled with mineral inclusions that look like underwater gardens, mossy landscapes, or floating scenery.
crystal
Pisolite
A sedimentary rock built from pea-sized concentric spheres called pisoids, often carbonate but sometimes iron or aluminum-rich.
sedimentary