Rock & Mineral Encyclopedia

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

Aventurine

A translucent quartz speckled with glittery mineral inclusions that produce a shimmering aventurescence, most often green.

A naturally blue quartz colored by tiny mineral inclusions such as dumortierite or scattered rutile and tourmaline fibers.

A translucent chalcedony agate whose mineral inclusions form miniature scenes resembling mountains, trees, deserts, and skies.

A translucent chalcedony agate containing delicate, feather- or plume-shaped mineral inclusions that branch like soft feathers.