The 9 large ones are 15/16" the long way, about 13/16" the short way, rounded rectangles that glow and shine. We think they're resin or a combination of resin and shell. They're very smooth, sleek and light in weight; too light to be glass or stone, but they look like shell, glass, and/or polished stone. The hole on the back is about 1.5mm.  No two will exactly match; eight are earth tones and one is layers of gray; all glisten with tones of gold and silver. 

Two smaller round ones are a bit smaller than 3/4" diameter, with an intricate arrangement of sparkles of bright gold beneath the clear resin top, and shanks on the back with 1mm openings. 

Age unknown. Condition perfect.  You'll get all eleven buttons; the exact ones shown.. Exceptional. Japan.