This is a loose lot of 2 buttons that are matching in style but not size. I first thought they were Bakelite but they did not pass the test. They are possibly bone. They don't really feel like plastic. The centers are brass, very Art Deco in design. The brass inset goes though the bone part to form a brass shank on the back. One is 1 inch. The other is 1 1/8 inch. These are old, probably from the 1930s. I think these buttons would work in jewelry beautifully.
Please note that button purchases can be combined to save on shipping. At least 3 lots,often more, will go for the one shipping rate. I automatically give refunds when lots are combined.