Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Khondalite
A high-grade metamorphic gneiss of garnet, sillimanite, quartz, and graphite, derived from ancient aluminous sediments.
metamorphicRegency Rose Agate
A prized plume agate with rose-pink and red feathery inclusions suspended in clear chalcedony, from the western U.S.
gemstone
Green Marble
A green ornamental stone, often serpentine-rich marble or verde antique, valued for its rich green color and white veining.
metamorphic
Calc-schist
A foliated metamorphic rock of calcite mixed with mica, quartz, and calc-silicate minerals, derived from marly sediments.
metamorphic
Garnet Schist
A shiny, foliated schist studded with red garnet crystals that grew during medium-grade regional metamorphism.
metamorphic
Boulder Opal
Precious opal that forms in thin veins within brown ironstone boulders, cut with the host rock left as a natural dark backing.
gemstoneStarburst Agate
Agate containing radiating sprays of mineral needles that fan out like bursting stars within the chalcedony.
gemstone
Sweetwater Agate
A translucent Wyoming chalcedony filled with delicate black manganese dendrites that resemble tiny ferns, moss, or starbursts.
gemstoneLace Obsidian
Black volcanic glass laced with delicate web-like veins of contrasting color, formed by flow banding and fine crystallization.
igneousBird's Eye Jasper
A microcrystalline quartz jasper marked by small concentric ring or eye patterns that resemble the eyes of birds.
mineral
Sodalite
A royal-blue feldspathoid mineral with white calcite veining, often confused with lapis lazuli but lacking its golden pyrite flecks.
mineralCloud Agate
A chalcedony agate with soft, billowing cloud-like masses of gray and white suspended in a translucent body.
gemstoneFrost Agate
A pale chalcedony agate with cloudy, frost-like white patterning suggesting frost on a window or icy crystalline textures.
gemstone
Honey Agate
A warm golden to amber translucent chalcedony agate whose color and glow resemble honey, sometimes with banding.
gemstoneSunset Agate
A warmly colored chalcedony agate with reds, oranges, golds, and pinks that blend like the glowing bands of a sunset sky.
gemstonePolyhedroid Agate
A rare agate that forms naturally with flat polygonal faces and angular geometric shapes rather than the usual rounded nodule.
gemstone
Brecciated Jasper
A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.
sedimentaryNoreena Jasper
A rare Australian jasper from the Pilbara with bold red, yellow, and black abstract patterns, prized by collectors.
mineralStarry Night Jasper
A dark jasper trade stone speckled with pale flecks resembling a starry night sky, valued for its cosmic appearance.
mineralFireworks Obsidian
Black volcanic glass dotted with radiating spherulite bursts that look like exploding fireworks frozen in the stone.
igneous
Landscape Opal
A common opal containing dendritic or mossy mineral inclusions that form miniature landscape-like scenes inside the stone.
gemstone
Thulite
A pink, manganese-rich variety of zoisite used as an ornamental gemstone, often mottled with white quartz and grey matrix.
gemstoneDouble Flow Obsidian
Obsidian formed from two merged lava flows, producing a stone with two distinct bands of sheen or color.
igneous
Leopard Opal
A patterned common opal with mottled, leopard-like spots and blotches, prized as an ornamental and cabochon stone.
gemstone