Marble with
serpentine; Ledmore, Assynt, NW Scotland
This rock formed from a dolomitic limestone (calcium
magnesium carbonate) with some silica impurities. High grade
metamorphism formed the mineral olivine (magnesium
silicate). Along bands and fractures, where water got in
while the rock was still hot, this has been converted to the
distinctive yellow-green colour of serpentine (hydrated
magnesium silicate). Serpentine-rich marbles are commonly
quarried, cut into slabs, and used for decorative purposes.