Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Vogesite
A dark hornblende-rich lamprophyre dike rock with amphibole and augite phenocrysts in an alkali-feldspar-dominated groundmass.
igneous
Kersantite
A dark mica lamprophyre with biotite and augite phenocrysts in a plagioclase-dominated groundmass, the feldspar counterpart of minette.
igneous
Travertine
A banded, porous limestone deposited by mineral springs, prized as a warm-toned natural building and tile stone.
sedimentary
Calcrete
Carbonate-cemented soil crust formed in arid regions where calcium carbonate accumulates and hardens within the regolith.
sedimentaryLithographic Limestone
Extremely fine-grained, even-textured limestone famous for lithographic printing and for preserving exquisite fossils like Archaeopteryx.
sedimentary
Plagioclase
The most abundant rock-forming feldspar group, a continuous solid-solution series from sodium albite to calcium anorthite that builds much of the crust.
mineral
Blue Chalcedony
A translucent, soft blue variety of microcrystalline quartz whose color comes from light scattering through its fine structure.
mineral
Micrite
A very fine-grained limestone made of microcrystalline calcite mud, dense and smooth, deposited in calm carbonate settings.
sedimentary
Angelite
A soft pale-blue calcium sulfate, the anhydrous form of gypsum, prized as a gentle, calming tumbled stone.
mineralBlue Line Jasper
A pale jasper crossed by distinctive blue-gray veins or lines, valued by lapidaries for its calm color contrast.
gemstone
Lotus Jasper
A softly patterned jasper in cream, gray, and tan whose markings can suggest lotus petals, popular for calm, neutral-toned jewelry.
gemstoneOwyhee Blue Agate
A soft sky-blue chalcedony from the Owyhee region of Oregon and Idaho, prized for its calming, opaque powder-blue color.
gemstoneOwyhee Blue Jasper
A soft blue-gray jasper from the Owyhee region of Oregon and Idaho, prized for its rare, calming blue tones among earthy jaspers.
gemstone