Studs (?)

While going through some acquired Civil War items (just to relate to dates from the late 1800's), I came across 2 stud's or buttons. I don't know how to describe them. They appear to be mother-of-pearl inlays on the top mounted on (1) the underneath side of an 1873 seated liberty half dime which is clearly visible. The other one is the same but mounted atop an 1876 seated liberty half dime. A jeweler of that period has to have made them because of the intricate workmanship. There are no hallmarks at all. I first thought they might have been cufflinks, then thought maybe studs for a dress shirt or even old button up shoes.