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.

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

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

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

Fine, golden, hair-like strands of basaltic volcanic glass spun from fluid lava droplets during eruptions, named for the Hawaiian volcano goddess.

Small, smooth, teardrop-shaped beads of basaltic volcanic glass formed from airborne lava droplets, often paired with Pele's hair.

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

An organic gem formed inside mollusks from layered nacre, prized for its iridescent luster and classic elegance.

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

A soft peach to pinkish-orange garnet, usually a malaia-type pyrope-spessartine blend prized for its warm, delicate color.

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

A deep, rich forest-green elbaite tourmaline (verdelite) colored mainly by iron, with strong pleochroism and excellent durability.

Ancient chemically deposited rock of alternating iron-oxide and silica bands recording Earth's early oxygenation and a major iron ore source.

A soft, fine-grained red metamorphosed claystone, sacred to many Native American peoples and carved into ceremonial pipes.