Antique solitaire button, with detachable shank which joins with a spring mechanism. This one has a black top with star-flower patter on a textured ground, inside a rope rim. Unidentified material but could be dyed pressed horn or possibly some kind of composition. I think it is too light to be black glass. Back stamped WEST’S PATENT with the GW monogram. Slight age related wear as shown, but interesting collectible.

Size 7/8” (2.2 cm)