Oregon Polka Dot Agate Cabochon ITEM # polkc1. This cab has pretty designs in browns to yellowish tones with a clear agate background (and top). A good size for a ringstone or bracelet or smaller pendant. Well cut with a top quality high gloss polish .. the back side is flat and smooth but not polished It measures approx. 23.8 x 14 mm and is 4.4 mm thick. A shallow or low dome and I cut it to be easy to set with a bezel. I have an American Quarter (25 cent) coin in one of the pictures to help you understand the size.