Gleaming facets of shine showcase the dramatic black color of the onyx 12mm faceted roundel beads from Dakota Stones. Available in 8-inch strands, these large rounded beads feature a glossy black color that is only enhanced by the diamond-shaped facets cut into their surface. 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 color enhanced to increase its depth of color. 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 the mystical birthstone for the month of December and is given as a gift on the seventh and tenth wedding anniversaries. Dakota Stones offers high-quality gemstones that are all useable in jewelry designs because every bead is checked to ensure they are cut and drilled correctly, that the finish is right and that the beads look distinct to their stone type.