Rock & Mineral Encyclopedia

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

Star Moonstone

A rare moonstone that shows a four-rayed star of light (asterism) across its domed surface along with adularescence.

Clear quartz filled with mineral inclusions that look like underwater gardens, mossy landscapes, or floating scenery.

A man-made opalescent glass that glows milky blue in reflected light and warm orange when backlit, often sold as a crystal.

Masasi Blue Garnet is a rare vanadium-bearing color-change garnet from Tanzania that appears blue-green by day and purplish-red indoors.

A porous limestone built from the calcium carbonate skeletons of corals and reef organisms, the lithified remains of ancient or modern reefs.

A copper-iron sulfide ore famous for its iridescent peacock-like purple and blue tarnish; often sold as treated chalcopyrite.

An orbicular jasper with red and orange flower-like spots resembling poppies, famously from Morgan Hill, California.

A pegmatitic granite in which quartz and feldspar intergrow to resemble ancient runic or Hebrew script.

A banded rhyolitic volcanic rock with swirling tan, red, and yellow iron-oxide layers prized as a decorative picture stone.

A dark gray-to-black feldspar variety of moonstone that shows blue and white adularescent flash against a smoky body.

A black-and-white striped chalcedony-quartz rock whose bold zebra-like banding makes it a popular ornamental and lapidary stone.

A prized Idaho jasper known for porcelain-smooth pastel pinks, creams, and greens in soft swirling, orbicular patterns.

A mica schist studded with brown staurolite porphyroblasts, sometimes forming the cross-shaped twins known as fairy stones.