Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Shungite
A rare black carbon-rich rock from Russia, noted for containing fullerenes and ranging from dull mineralized stone to lustrous noble shungite.
sedimentary
Acanthite
A silver sulfide that is one of the most important silver ore minerals, forming dark metallic crystals and wires.
mineral
Bituminous Shale
A dark, organic-rich shale loaded with kerogen and bitumen that can yield oil and gas, often finely laminated and combustible.
sedimentary
Leopard Skin Jasper
A spotted jasper-rhyolite patterned with leopard-like rings and ovals, valued as an earthy ornamental and lapidary stone.
sedimentary
Minette
A dark, mica-rich lamprophyre dike rock in which biotite and augite phenocrysts sit in a groundmass dominated by alkali feldspar.
igneous
Vogesite
A dark hornblende-rich lamprophyre dike rock with amphibole and augite phenocrysts in an alkali-feldspar-dominated groundmass.
igneous
Siderite
Siderite is an iron carbonate ore, a brown rhombohedral mineral of the calcite group found in sediments and veins.
mineral
Pelitic Schist
A schist derived from clay-rich sediments, rich in mica and often bearing index minerals like garnet, staurolite, or kyanite.
metamorphicUrtite
A pale, nepheline-dominated plutonic rock at the leucocratic end of the ijolite series, sometimes associated with major apatite ore deposits.
igneous
Anglesite
A heavy lead sulfate secondary mineral, often colorless to white with adamantine luster, formed by the oxidation of galena.
mineral
Tree Agate
A white chalcedony filled with green or black dendritic, tree-like mineral inclusions that resemble ferns or moss frozen in stone.
gemstone
Pyroxenite
A dense, dark ultramafic plutonic rock composed almost entirely of pyroxene minerals, often associated with peridotite and layered intrusions.
igneous
Pumpkin Obsidian
An orange-to-rust colored variety of natural volcanic glass whose warm tone comes from iron oxide staining within the obsidian.
igneous
Chalcocite
A dark gray copper sulfide that is one of the richest copper ores, prized by collectors when found as rare sharp crystals.
mineral
Gneiss
A high-grade metamorphic rock defined by alternating light and dark mineral bands, formed under intense heat and pressure.
metamorphic
Kambaba Jasper
A dark green-and-black stromatolite jasper patterned with swirling orbs, formed from fossilized ancient microbial colonies.
sedimentaryLace Obsidian
Black volcanic glass laced with delicate web-like veins of contrasting color, formed by flow banding and fine crystallization.
igneous
Bloodstone Jasper
A dark green jasper-chalcedony speckled with red iron-oxide spots, classically known as bloodstone or heliotrope.
mineral
Bronzite
An iron-rich orthopyroxene prized for its warm bronze schiller, a metallic-looking sheen created by tiny mineral inclusions.
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
Moss Agate
A translucent chalcedony filled with green or brown dendritic mineral inclusions that resemble moss, foliage, or landscapes.
gemstone
Crocoite
A striking lead chromate mineral prized for its brilliant orange-red prismatic crystals, with the finest specimens from Tasmania.
mineral
Potassium Feldspar
The potassium-rich feldspar group - orthoclase, microcline, and sanidine - a major rock-forming mineral often recognized by its salmon-pink color.
mineral
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