This brooch or pendant was probably a 1950's souvenir from Mexico. It is 1 7/8" across, set with a 1" polished green aventurine cabochon. The silver border has cut out figures of an Aztec or Mayan god and pyramids.
The brooch is marked 925 on the reverse. It has a bail, so can be worn as a pin or pendant. The silver has not been polished and has a vintage patina. the weight is 20.1 grams,