Dark color glints with gleaming shine in the onyx 10mm faceted round beads from Dakota Stones. Available by the strand, these beads display a round shape and facets cut into the surface to give these glossy black beads extra shine. Onyx is a variety of chalcedony that is similar to agate, with straight rather than curved bands. Nearly all black onyx on the market has been rendered a uniform, permanent black color with a treatment by sugar and acid or heat. This process has been used on onyx for thousands of years and does not decrease the value of the stone. Mined in Brazil, India and Madagascar, onyx is said to set one's mind to a task. Use these beads with clear crystal for a fabulous formal look.