Cotham marble, a very unique cabochon material, is a variety of Rhaetian stromatolite from south Wales and southwestern England. It is actually a fossil, or stromatolite. Stromatolites are some of the oldest known fossils, dating back more than 3 billion years! This material is from the Triassic Period and is about 220 million years old. Though called marble, these interesting stones with landscape scenes are actually limestone. Cabbed in large sizes to showcase their pastoral vistas, these stones make great pendants.
