1 3/4 inch diameter x 1/2 inch domed profile
Scuffs on domed lucite
It appears one may have been reset in a newer brass holder
The back loops are very different, the older one has holes where the loop ends attach and could account for the damage to the image
Horse or Pony Bridle Rosettes were at their most popular in the Victorian era and made use of the diecut & transfer designs that were all the rage, inserted/embedded into a glass or lucite domed rosette button with either a brass or steel back. They were made in pairs, each a mirror image of the other, with a D Ring back loop. 1 is slipped onto each end of the browband (the strap going across the horse's forehead) and then pushed back against the cheek straps, tightening the browband against the cheeks pieces to prevent slipping. Matched pairs are extremely hard to find. Bridle buttons can be repurposed as brooches or made into other jewelry pieces.