Rock & Mineral Encyclopedia

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

Polyhedroid Agate

A rare agate that forms naturally with flat polygonal faces and angular geometric shapes rather than the usual rounded nodule.

A rare Australian jasper from the Pilbara with bold red, yellow, and black abstract patterns, prized by collectors.

A brecciated, chatoyant quartz with swirling blue, gold, and brown fibers that shimmer like a stormy sky.

A bright yellow native element mineral that forms around volcanic vents and hot springs and burns with a blue flame.

A blue calcium phosphate mineral with vivid color and middling hardness, the same mineral family that forms bones and teeth.

A group of green magnesium silicate minerals with a smooth, waxy feel, often carved and sometimes sold as imitation jade.

A magnesium carbonate mineral, usually chalky white with grey veining, widely dyed to imitate turquoise and other stones.

A white, porous borate mineral webbed with gray-black veins, widely dyed to imitate turquoise and other stones.

A translucent agate whose mineral inclusions resemble miniature landscapes of trees, hills, and horizons within the stone.

A heavy, lead-grey metallic mineral with perfect cubic cleavage, galena is the world's main ore of lead and often carries silver.

A dark, mineral-rich dike rock with abundant mica or amphibole phenocrysts set in a fine groundmass, often associated with gold and diamonds.

A pink, manganese-rich variety of zoisite used as an ornamental gemstone, often mottled with white quartz and grey matrix.

A dense, dark ultramafic plutonic rock composed almost entirely of pyroxene minerals, often associated with peridotite and layered intrusions.