damn took me a few good looks to figure out what the glass like sheen was, it's wrapped in a coin collectors cartouche, with the transparant plastic window.
looks like a medaillon, prolly one of many. These were sold near places of worship and were good business for the church.
This one seems to haven't completely filled out the mold, hence the gap near the bottom.
edit: rule of thumb, always display a ruler near the object, size is a very important marker to identify coins and the like.