Unusual Estate Treasure Luxury Painted Stone? Photo or Mirror Frame

Unusual Estate Treasure - Luxury Painted Photo or Mirror Frame Patina seems consistent with being an antique or vintage, and was in an estate sale with many other historic objects Appears to be carved out of a single piece of white stone, or possibly a polymer or other manufactured mineral based material Heavy for its size and feels like stone Approximately 9.5" x 7.75" x 1" thick Weighs 1 lb 10oz Unknown origin Unidentified artist A stunning mystery Offers welcome