Sea jasper, or orbicular or fisheye jasper is composed of silicified rhyolite, and is found solely on the northwest coast of madagascar, where it is mined from the beach. The name jasper is derived from the Greek, meaning "spotted stone"; it is so-named for the many spheres or orbs in its matrix, which appear as circles or eyes in cut cross-section. These formations typically range in size from 1mm to 1cm, but the exact process of their formation is still unknown.