Mexican Harlequin Opal Art Glass Pendant Pin Sterling Silver

Vintage 1930s Mexican sterling silver pendant brooch that is set with a harlequin art glass opal. It is foiled on the back and has blue flash like a dragon's breath stone does. Nice denim blue color. Stone measures 19mm by 14mm and the pendant is 1 1/2" by 1 3/8". Locking clasp. Bail is on the back. Weight: 10.4 grams. Stone has some scratches that do not affect the brilliance of it at all. Silver is tarnished. 

Here it is in the sun: