Rock & Mineral Encyclopedia

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

Multicolor Tourmaline

Tourmaline crystals displaying two or more distinct colors at once, including the famous pink-and-green watermelon variety.

A coarse-grained, feldspar-free plutonic rock composed mainly of nepheline and sodic pyroxene, the intrusive equivalent of nephelinite.

A prized plume agate with rose-pink and red feathery inclusions suspended in clear chalcedony, from the western U.S.

A creamy pink-and-white chalcedony from Madagascar containing flower-like plume inclusions that resemble blossoms suspended in stone.

A multicolored orbicular chalcedony from Madagascar famous for its circular eye-like orbs in greens, pinks, whites, and yellows.

A deep wine-red to maroon tourmaline colored by manganese, a rich darker-toned member of the red-pink rubellite family.

A prized plume agate from near Carey, Idaho, showing red, pink and black feathery plumes floating in translucent chalcedony.

A group of coarse, water-rich plutonic rocks dominated by large hornblende crystals set in feldspar, intermediate between lamprophyre and diorite.