Rock & Mineral Encyclopedia

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

Sardonyx

A banded chalcedony combining reddish-brown sard with white or black onyx layers, prized since antiquity for carved cameos.

A warm orange-to-red variety of chalcedony quartz colored by iron oxide, used since antiquity for seals, beads, and cabochons.

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

A rare, prized Oregon picture jasper known for blue-green orbs and scenic patterns, often called the king of jaspers.

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

A jasper marked with soft feather- or plume-like mineral inclusions that drift through a pale silica body.

A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.

A gray-toned jasper with swirling cream, black, and brown leaf-like patterns, sometimes with druzy or agate pockets.

A hollow rock nodule whose interior cavity is lined with inward-pointing crystals such as quartz, amethyst, or calcite.

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

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

A chalcedony agate filled with radiating needle-like mineral inclusions, prized for its starburst and spray patterns.

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

Agate containing radiating sprays of mineral needles that fan out like bursting stars within the chalcedony.