Rock & Mineral Encyclopedia

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

Citrine

The golden-yellow variety of quartz, ranging from pale lemon to deep madeira amber, often produced by heating amethyst.

A red-toned banded chalcedony colored by iron oxides, ranging from natural carnelian-like reds to heat-treated stones.

A vivid greenish-yellow quartz, usually heat-treated or irradiated, prized for its clean clarity and bright lemon color.

A pale green variety of quartz, usually created by heat-treating amethyst, often marketed as green amethyst.

A natural bicolor quartz that combines purple amethyst and golden citrine in a single crystal.

The yellow variety of beryl, also called heliodor or golden beryl, colored by iron and valued for its bright color and durability.

A cheerful yellow opal ranging from translucent common opal to golden fire opal, colored by trace iron in the silica.

A treated chalcedony with a network of crackled veins, usually heated and dyed in vivid colors for affordable, eye-catching beads.