Like many antique/vintage lockets, the interior structure of the locket is made of a different metal, to give it strength. The gold is just on the exterior of the locket. The hinges & catch are both in excellent condition. It measures about 1” wide & about 1/8” thick. It is very lightweight & has a lovely patina. As it has no marks, it is impossible to accurately date, but I estimate 1920-1950. It came from a dealer in South America, so perhaps that is where it was made.
A horse is featured on this locket, wearing a bridle, complete w a red stone rosette (probably a garnet or spinel). The horse is framed with a lucky horse shoe. The heels of the shoe are facing downward to let good luck wash over the lucky person who gets to wear this locket.