Rock & Mineral Encyclopedia

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

Potassium Feldspar

The potassium-rich feldspar group - orthoclase, microcline, and sanidine - a major rock-forming mineral often recognized by its salmon-pink color.

A multicolored orbicular chalcedony from Madagascar famous for its circular eye-like orbs in greens, pinks, whites, and yellows.

A banded variety of chalcedony quartz, classically black or black-and-white, long favored for cameos and beads.

A banded variety of chalcedony quartz, famed for its colorful concentric layers and enormous range of patterns and colors.

Rutile is a major titanium ore and the famous golden needle inclusion that gives rutilated quartz its shimmering threads.

A vivid blue-green hydrated copper silicate, soft on its own but prized as a gem when hardened by intergrown quartz or chalcedony.

A bright strawberry-red garnet, typically an almandine-pyrope blend prized for its juicy, lively red color in jewelry.

A precious opal pattern made of tiny, densely packed pinpoint flashes of play-of-color, like sparkling speckles across the stone.

The classic green ornamental gem, either jadeite or nephrite, valued for millennia for its toughness and rich color, especially imperial green.

The serene blue-to-sea-green variety of beryl, aquamarine is a durable gemstone colored by trace iron and birthstone for March.

The blue color variety of beryl, ranging from pale sky tones to rich sea-blue, best known in its finest grades as aquamarine.

A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.