gabbro

gabro puhekieltä A name originally given to a kind of serpentine, and now generally used for a coarsely crystalline, igneous rock consisting of lamellar pyroxene and labradorite.
2004, (w), The Earth, Folio Society 2011, p. 59:

It is known as gabbro and is thought to form the lower layer of the oceanic crust at about four kilometres depth and to comprise a layer up to six kilometres thick, making it one of the most abundant, if least recognisable, materials on earth.