“Green marble” is often available from granite & marble companies. However, the actual material is not even close to what the term “green marble” implies or suggests. “Green marble” is actually serpentinite, which results from the metamorphism of olivine-rich ultramafic igneous rocks (peridotites). Serpentinites are principally composed of serpentine, although small amounts of magnetite are often present.
“Green Marble” - serpentinite (undetermined commercial name; undetermined provenance).
Verde Mare Marble - serpentinite from the Italian Alps. Minerals reported from this unit include antigorite serpentine, forsterite olivine, diopside pyroxene + accessory chlorite, titanian magnetite, and local chrysotile asbestos.
Geologic Unit & Age & Alteration History: Malenco Serpentinite (a.k.a. Malenco Peridotite; Val Malenco Peridotite; Malenco Ultramafics; Malenco Ophiolite) - largely serpentinized subcontinental mantle of Permian age, uplifted to seafloor exposure in the Jurassic, deformed as an ultrmafic nappe metamorphosed to epidote-amphibolite grade during the Alpine Orogeny in the Oligocene-Miocene.
Locality: commercial quarry near town of Val Malenco, Lombardy Region, Raethian Alps (east-central Alps), near border with Switzerland, far-northern Italy.