Vintage cherry red leaves brooch signed Siam Sterling

About 1-3/4 X 1-1/4 inches, this brooch has a dancer motif etched in deep red enamel on leaves with beautifully sculpted edges. Marked Siam Sterling on the back. Although I know this style of jewelry is vintage, I am not sure of the the exact age, as Siam Sterling continued as a jewelry mark after Siam became Thailand in 1939. The brooch is in very good condition, with great colour and details and very little tarnish.