I believe this brooch to date to the mid 1800's and almost certainly would have originated in Italy. Probably a grand tour souvenir. It features a micro mosaic of a bird set into a raised glass mount. There may be a tile missing at the bottom but I think it could just as easily be a small gap in the mosaic which was never filled.
Please examine the photos to judge for yourself. The mount does have a crack right the way across on the back which can also be noticed on the front but the micro mosaic is tight and the crack is barely visible from the front. It is mounted on to a gold coloured rope twist border.It measures approx 3.6cm x 3cm. The item "Victorian micro mosaic grand tour brooch of bird" is in sale since Friday, July 9, 2021. This item is in the category "Jewellery & Watches\Vintage & Antique Jewellery\Vintage Costume Jewellery\Victorian (1837-1901)". The seller is "antiguadivin" and is located in Newark. This item can be shipped worldwide.