Rock & Mineral Encyclopedia

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

Ametrine

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

The smoky brown to gray variety of quartz, colored by natural irradiation, valued as both a gemstone and crystal specimen.

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

A green quartz speckled with shimmering fuchsite mica that produces a glittering aventurescence, popular as an affordable ornamental stone.

The darkest, near-opaque black variety of smoky quartz, colored by natural radiation acting on trace aluminum.

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

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

A quartz with a complex skeletal, layered surface of many terminations and etched recesses, also called skeletal or jacare quartz.

Clear or smoky quartz threaded with golden to reddish needles of rutile, also poetically called Venus hair stone.

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

A trade name for quartz containing a combination of seven minerals including amethyst, smoky quartz, and cacoxenite, prized by collectors.

An altered granite of pink feldspar, green epidote and quartz, mottled pink-and-green and popular as a tumbled and carving stone.

An opaque, often colorfully patterned variety of chalcedony quartz, popular for tumbling, carving, and jewelry.