Rock & Mineral Encyclopedia

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

Aventurine

A translucent quartz speckled with glittery mineral inclusions that produce a shimmering aventurescence, most often green.

A warmly colored chalcedony agate with reds, oranges, golds, and pinks that blend like the glowing bands of a sunset sky.

A chalcedony agate with soft, billowing cloud-like masses of gray and white suspended in a translucent body.

Also called Sci-Fi Jasper, a Mexican jasper-rhyolite with swirling abstract patterns in cream, tan, gray, pink, and green.

A fortification agate from the Black Hills of South Dakota, known for tight, colorful banding closely related to the famous Fairburn agate.

An opaque brown chalcedony whose iron-stained banding mimics deserts, dunes, and distant mountain skylines.

A translucent milky quartz that shows a soft, floating blue-white glow when light passes through it.

An opaque green variety of chalcedony quartz colored by iron and chlorite-group inclusions, prized as a durable carving and cabochon stone.

A dark green jasper-chalcedony speckled with red iron-oxide spots, classically known as bloodstone or heliotrope.

A dense, opaque black variety of microcrystalline quartz historically used as a touchstone for testing precious metals.

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

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

A prized Namibian quartz combining amethyst, smoky, and clear quartz in single crystals, often with phantoms and enhydros.

A translucent Wyoming chalcedony filled with delicate black manganese dendrites that resemble tiny ferns, moss, or starbursts.