The Catoctin Greenstone500 million year old ocean crust from the Shenandoah region of Virginia. From a time when the supercontinent was Rodina and the proto-Atlantic Ocean was called Iapetus. View fullsize "Shades of Catoctin" - Catoctin Formation Greenstone from Virginia, red slate, black slate, smalti, glass rods, glass beads. 8.25" x 8.25" (Available) View fullsize "Catoctin Mini" - Catoctin Formation Greenstone from Virginia with slate, smalti, glass beads and beach pebbles from Washington State. On Wediboard with tinted thinset. 4.25" x 5" (NFS)