Beautiful Modernist sterling silver brooch with inlaid green polka dots.
Oval shape, very clean lines.
Shiny Sterling silver and emerald green inlay material*
Superb craftsmanship. 
The photos do not do this piece justice.
*Los Ballesteros made a bracelet with inlaid Bakelite dots. It matches this piece.
I tested with Simichrome and it did not test as Bakelite. I am unsure what the material is. 

HALLMARK/LABEL: Talleres de Los Ballesteros, 925 Sterling, Taxco, Hecho en Mexico

MEASUREMENTS: 2 1/2" x 1 1/8" W

CONDITION: Beautiful, shiny, no dents. Signs of wear and light surface scratches. Overall just beautiful. 

MATERIAL: 925 Sterling Silver, green inlaid. 
GRAMS: 21.3