It appears to be fine quality pocket ... watch crystal which would have been visible in the center. I do not have the watch and I suspect this dial was salvaged from it during the great gold ...
Perpetual Calendar Pocket Watch $24 million 1948 Patek Philippe & Co. 18K Gold & Enamel Pocket Watch $12.5 million 1900 Patek Philippe & Co. 18K Gold Pocket Watch $2.25 million The most expensive ...