Rock & Mineral Encyclopedia

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

Alexandrite

A rare color-change chrysoberyl that appears green in daylight and red under incandescent light, sometimes called emerald by day, ruby by night.

A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.

A striking lead chromate mineral prized for its brilliant orange-red prismatic crystals, with the finest specimens from Tasmania.

A brilliant orange-red lead vanadate mineral forming hexagonal crystals, prized by collectors and mined as an ore of vanadium.

A shiny, foliated schist studded with red garnet crystals that grew during medium-grade regional metamorphism.

A rare ferric-iron-dominant tourmaline that forms in oxidized evaporite settings, appearing as black to red-brown prismatic crystals.

Rhodochrosite is a rose-pink manganese carbonate prized for raspberry-red crystals and banded pink-and-white gem material.

A black metallic manganese iron oxide famous for sharp cubic crystals, classically found with red beryl and topaz in Utah rhyolite.

A dark gray copper sulfide that is one of the richest copper ores, prized by collectors when found as rare sharp crystals.

Clear or smoky quartz threaded with golden to reddish needles of rutile, also poetically called Venus hair stone.

A man-made glittering glass packed with tiny copper crystals, traditionally reddish-brown but also made in blue and green.

Agate that was shattered and naturally re-cemented by silica, creating a mosaic of angular fragments in a quartz matrix.

Tabular quartz crossed by a milky white thread-like line marking where the crystal repeatedly cracked and re-healed.