Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Kambaba Jasper
A dark green-and-black stromatolite jasper patterned with swirling orbs, formed from fossilized ancient microbial colonies.
sedimentary
Limburgite
A dark, glass-rich volcanic rock of olivine and augite phenocrysts set in a feldspar-free glassy groundmass, named from the Kaiserstuhl region.
igneous
Picture Jasper
An opaque brown chalcedony whose iron-stained banding mimics deserts, dunes, and distant mountain skylines.
mineralSandstone
A clastic sedimentary rock made of cemented sand grains, often quartz, recording ancient beaches, deserts, and rivers.
sedimentary
Lindi Garnet
Lindi Garnet is a rare vanadium-rich color-change garnet from Tanzania's Lindi region, shifting from blue-green daylight tones to purple-red.
gemstoneDragon Blood Jasper
A green-and-red ornamental stone of epidote and red piemontite or iron oxide, named for its dragon-skin coloring; not a true jasper.
metamorphic
Dacite
A fine-grained volcanic rock intermediate between andesite and rhyolite, common at explosive stratovolcanoes.
igneous
Peacock Ore
A copper-iron sulfide ore famous for its iridescent peacock-like purple and blue tarnish; often sold as treated chalcopyrite.
mineral
Trachyte
A fine-grained volcanic rock dominated by alkali feldspar, the extrusive equivalent of syenite.
igneousRainforest Jasper
An Australian green rhyolite with eye-like orbs and earthy patterns marketed as jasper, evoking dense rainforest foliage.
igneous
Suevite
A rare breccia formed by meteorite impact, containing shocked rock fragments and glassy melt blobs welded together.
metamorphic
Greywacke
A hard, dark, poorly sorted sandstone with a muddy matrix, typically deposited by underwater turbidity currents.
sedimentary
Metaconglomerate
A conglomerate altered by heat and pressure, often with its rounded pebbles stretched and flattened into elongated lenses.
metamorphic
Charnockite
A granite-like rock containing orthopyroxene, formed at high temperatures and pressures and often classed with the granulites.
igneous
Biotite Schist
A foliated metamorphic rock dominated by glittering dark biotite mica, formed from mudstones under medium-grade regional metamorphism.
metamorphic
Metaquartzite
A hard, tough metamorphic rock of fused quartz grains, formed by recrystallizing quartz sandstone under heat and pressure.
metamorphic
Black Shale
Dark, organic-rich fine-grained sedimentary rock formed in oxygen-poor waters, often a source rock for oil and gas.
sedimentary
Talc Schist
An extremely soft, soapy-feeling foliated rock made largely of talc, formed by metamorphism of magnesium-rich rocks.
metamorphic
Chlorite Schist
A soft, green, foliated rock rich in chlorite, formed by low-grade metamorphism of mafic or volcanic rocks.
metamorphic
Lamproite
A rare ultrapotassic, magnesium-rich volcanic rock from deep in the mantle, famous as the diamond host at Argyle in Australia.
igneous
Graphic Feldspar
A pegmatite rock of feldspar intergrown with wedge-shaped quartz that resembles ancient runic or Hebrew writing.
igneous
Mustard Jasper
A warm mustard-to-ochre yellow jasper colored by iron, valued by lapidaries for its rich, earthy golden tone.
gemstoneWonderstone
A banded rhyolitic volcanic rock with swirling tan, red, and yellow iron-oxide layers prized as a decorative picture stone.
igneousSlate
A fine-grained, low-grade metamorphic rock that splits into flat sheets along slaty cleavage, long used for roofing and flooring.
metamorphic