Costume-jewelry expert Kathy Flood has two pages featuring this exact sort of accessory in her tome ""The Jewelry Face Book of Pins Pendants: Vintage Visages." On page 33, the author notes that "They are colored-sand-art pins...using something like sand cloisonné: Metal strips create the outlines and various colors of sand fill the spaces made...Age unknown but not contemporary."
This particular example of this sort of artistry measures 2 1/2" x 2 1/16" and is in excellent vintage condition. There is a bit of darkening to the major earring at the lady's left but this is evidently part and parcel of what happened as this piece was lovingly created by hand, as opposed to being created by a cookie-cutter machine. (Please see last photo.) A portion of the sticker reading that this brooch was made in the Philippines remains on the underside.