I've now got my photos of gabbro that I took looking through a microscope in Dudley Museum at Easter. I love the textures of these readymade abstract images.
You can't trust Wikipedia for everything but this is probably correct:Gabbro (pronounced /ˈɡæbroʊ/) refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass.The vast majority of the Earth's surface is underlain by gabbro within the oceanic crust, produced by basalt magmatism at mid-ocean ridges. Gabbro is dense, greenish or dark-colored and contains pyroxene, plagioclase, amphibole, and olivine (olivine gabbro when olivine is present in a large amount). Gabbro is an essential part of the oceanic crust... UsesGabbro often contains valuable amounts of chromium, nickel, cobalt, gold, silver, platinum, and copper sulfides.Ocellar varieties of gabbro can be used as ornamental facing stones, paving stones and it is also known by the trade name of 'black granite', which is a popular type of graveyard headstone used in funerary rites. It is also used in kitchens and their countertops, also under the misnomer of 'black granite' Gabbro was named by the German geologist Christian Leopold von Buch after a town in the Italian Tuscany region
