Here is an unusual seahorse hair clip made by Los Castillo of Taxco, Mexico. It is made of silver (not sterling) set with abalone shell. It measures 2 1/2" X 1 1/8". Fully hallmarked for Los Castillo of Taxco The two pieces that make up the clip part are a little difficult to get into the prongs. It may have to be adjusted somehow. There are two tiny areas at the back of the head that I have shown in a photo where there is damage. Also there is a crack in the abalone shell but that may just be its natural state.
Los Castillo Mexican Silver Abalone Sea Horse Hair Clip