Rock & Mineral Encyclopedia

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

Blueschist

A blue-hued, high-pressure metamorphic schist colored by the amphibole glaucophane, formed in cold, deep subduction zones.

A coarse-grained alkali syenite of perthitic feldspar with sodic pyroxene or amphibole and minor nepheline, from Pulaski County, Arkansas.

One of the two jade minerals, an amphibole prized for its extreme toughness and soft, waxy green hues used in carving for millennia.

A spectacularly banded agpaitic nepheline syenite of alternating red eudialyte, black amphibole and white feldspar layers from Ilimaussaq, Greenland.