This is an antique, circa 1900, framed tondo (round picture) done in reverse glass painting with mother of pearl or abalone highlights. The image is of a mosque in Antioch which is now part of Turkey, though formerly part of Syria. The painted image is signed and it is framed with a gilded molded plaster gesso square frame with ivy vines. This is decorative wall art and likely was a Grand Tour souvenir item. The estimate is based on actual recent past recorded auction sales of comparables. Retail 'asking prices' can be higher and vary.