Rock & Mineral Encyclopedia

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

Amethyst

The purple variety of quartz, colored by iron and natural irradiation, prized as the classic violet birthstone of February.

A prized Namibian quartz combining amethyst, smoky, and clear quartz in single crystals, often with phantoms and enhydros.

A South African quartz whose central crystal is coated in tiny druzy points, also called cactus or fairy quartz.

A green variety of macrocrystalline quartz, usually the heat- or radiation-altered prasiolite, prized for its soft mint hue.

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

Quartz with a wider crystal 'cap' that grew over a narrower stem, forming a natural scepter or mushroom shape.

A natural bicolor quartz blending amethyst purple with prasiolite green in a single crystal, prized as a metaphysical heart-crown stone.

Quartz with a stepped, multi-pointed structure of parallel side crystals resembling the spires of a cathedral.

A South African quartz whose central crystal is coated in a cactus-like crust of tiny secondary points, also called spirit quartz.

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

Natural emerald crystals still embedded in their host rock, prized as mineral specimens that show how the gem grew in place.

The hardest known natural material, a crystalline form of pure carbon prized as the ultimate gemstone for its brilliance and fire.