Rock & Mineral Encyclopedia

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

Chrysoprase

A translucent apple-green chalcedony colored by nickel, the most prized green variety of the quartz family.

A microcrystalline quartz jasper marked by small concentric ring or eye patterns that resemble the eyes of birds.

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.

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

A natural volcanic glass with rich brown and black mahogany-like swirls created by iron oxide inclusions.

A dark, foliated schist rich in needle-like hornblende crystals, formed by metamorphism of mafic igneous rocks.