Round shaped black and white semi precious gemstone Tuxedo Agate designer cabochon 78 mm (3 inches!) in diameter and 5 mm thick.
This one does have a small natural flaw just above the large white area, visible in the pictures but not so much to the naked eye!
This is actually semi precious stone Brazilian Agate that has been dyed a rich black!
The natural white lines come through and make a beautiful specialty designer cabochon known as Tuxedo Agate.
Agate is a form of Chalcedony, or a microcrystalline quartz. It forms in concentric layers in a wide variety of colors and textures. It has a hardness of 7 and wears great in jewelry.