They are ancient rocks formed beneath the earth's surface and contain iron, hematite, magnatite and other heavy metals. The rocks are extremely heavy and the layers vary as to colors and patterns. This is a semi-prescious gemstone that is made into pendants, rings, beads and other jewelry. The fact that they are so old - sometimes over a million years old - makes them one of my favourites -- some were formed over 3700 million years ago, making these some of the oldest rocks on earth!
