Rock & Mineral Encyclopedia

Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.

Super Seven

A trade name for quartz containing a combination of seven minerals including amethyst, smoky quartz, and cacoxenite, prized by collectors.

A rosette-shaped cluster of bladed gypsum or barite crystals that traps sand, forming flower-like formations in arid deserts.

A nodular rhyolite geode-like ball whose plain exterior hides a star-shaped agate or chalcedony core when cut.

A nickel sulfide famous for delicate brass-yellow hairlike crystals that form radiating sprays inside cavities and geodes.

A plume agate whose inclusions form upright, bristly clusters resembling the strokes of a paintbrush.

A jasper whose radiating mineral clusters form flower-like rosettes scattered across an earthy background.

A calcium carbonate mineral and polymorph of calcite, aragonite forms distinctive needle clusters, sea shells, and pearls.

Stibnite is the chief ore of antimony, famous for its dramatic clusters of bladed, silvery-gray metallic crystals.

Obsidian that has partly crystallized over time, growing pale spherulite clusters within the black glass, as in snowflake obsidian.

A rare opal pseudomorph from White Cliffs, Australia, formed as opal replaced clustered crystals into a pineapple-like shape.

A translucent yellow-green silicate famous for its botryoidal 'grape' clusters, often hosting needle-like sprays of black epidote.