Vintage Sterling MAG Native Brooch-Pendant Signed Bergamo?

Beautiful vintage MAG (Metal Art Group) brooch-pendant signed by the designer -- looks like Bergamo. Nice raised relief tribal native design in sterling silver with tinting in the recessed areas for a feeling of depth. Some of the tinting is worn as shown, but it's in otherwise great vintage condition. Pin-pendant measures 1 1/4" x 3/4" and is marked MAG Sterling on back. The delicate link chain is marked 925 on clasp and measures 24" long.