The size of these big coin pearls is 16.5-17mm. That's pretty big for coin pearls. They have a lot of luster. Not perfect in shape, but very nice for the price. We think you will appreciate the rich color of these coin pearls as well. Freshwater coin pearl beads are created when a small flat disc shaped shell, instead of a round bead, is inserted into the oyster or more commonly these days, mussel. Most of these pearls are farmed in rivers, lakes or streams. The result is a a fabulous flat disc shape pearl. Our freshwater coin pearl beads are picked by their luster and size.