The serpentine rocks belonging to the metamorphic region of Connemara, West of Ireland, fall into two classes, the ophicalcites and the serpentinized basic igneous rocks.

The existence of exceptionally beautiful pale green and yellow serpentine and variegated ophicalcites is well known. At one time these deposits were quarried at several points, notably at the Lissoughter Quarry near Recess, the Derryclare Quarry on the eastern shores of Derryclare Lough, the Barnaoran Quarry near the head of the Owenglin River which flows into Clifden Bay, and at the Streamstown Quarry situated at the head of Streamstown Bay. There are, however, a number of other localities scattered through the region where small occurrences of ophicalcites and serpentinized igneous rocks are to be found.