Vintage Mexican Sterling Silver Brooch set with Black Coral

Vintage Mexican sterling silver brooch. It Is decorated with appliqué work and set with black coral. It measures 2 3/8" by 1 3/8". Non-locking clasp. Hallmarked on the back near the bottom, but marks are incomplete. Acid tested sterling. Weight: 15.6 grams. Tarnished. C. 1930.