Rock & Mineral Encyclopedia

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

Smoky Quartz

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

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 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 quartz with a main point surrounded by many smaller crystals along its sides, resembling melted candle wax, mainly from Madagascar.

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.

A hard, dark, poorly sorted sandstone with a muddy matrix, typically deposited by underwater turbidity currents.

Agate that was shattered and naturally re-cemented by silica, creating a mosaic of angular fragments in a quartz matrix.

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

A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.

An intermediate plutonic rock with nearly equal alkali and plagioclase feldspar and very little quartz, sitting between diorite and syenite.