Onyx

Onyx is a variety of microcrystalline silicon dioxide or chalcedony. It is often banded with white and used for cameo carvings. Most varieties of onyx, including black, are the result of dying. These dyes have been used for hundreds of years. Onyx is often used for rosary beads, as the Christians held on to the pagan beliefs that onyx had great medicinal benefits. Onyx was thought to make wounds heal faster and childbirth go smoothly.