Like the others on this page, these cat's eye beads are the real thing -- all natural stone, with no synthetic materials, like those other "cat's eye" beads that come in all the pretty colors. This is how they actually come from Mother Nature. These beads vary in size, although they all are coffee bean, or oval shapes. The beads vary in size, some being around 16 mm x 10 mm x 8 mm, and ranging to about 13 mm x 8 mm x 6 mm. This is a very cool, different looking stone which doesn't seem to have been "discovered" yet -- possibly due to its relative rarity. It is not the easiest stone to find! Sold by the piece.