Ink Well?

This is an antique cloisonne piece, but I don't know what it is. I got it from a 92 year old friend who just passed away. She had many items from France since her dad was from there. Any ideas? The bottom is solid blue with a dime sized hole in the center. The cracked white insert is thimble shaped and about 1.25 inches long. It measures 2.5 across the base and 2 inches tall. Thank You!