This is a vintage handmade sterling silver brooch by Francisco Rivera. It has turquoise gemstones and many marks, Taxco 925, eagle 3, Mexico and a distinctive R for Francisco Rivera.
Francisco Rivera worked for William Spratling. Most of his work was marked "Emma", for whom he designed and produced jewelry. Billie Hougart states that was a talented designer and silversmith - "The Little Book Of Mexican Silver Trade And Hallmarks". Sterling silver Francisco Rivera Taxco brooch can be found here.