Serpentinite

Serpentinite a rock composed of one or more serpentine group minerals. The name originating from the similarity of the texture of the rock to that of the skin of a snake.

Minerals in this group, which are rich in magnesium and water, light to dark green, greasy looking and slippery feeling, formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth’s mantle. The mineral alteration is particularly important at the sea floor at tectonic plate boundaries.

Serpentinite called serpentine or serpentine rock, particularly in older geological texts and in wider cultural settings.