Coro Gold Tone Circle Brooch Prong Set Rhinestone

This is a gold multi-circle brooch or pin from Coro. It has a large prong set rhinestone in the center. Very pretty. Excellent condition. However when looking at it and through the loops, a bottom one has like a little raised area. I don't know what it is. It just looks like a manufacturing issue. Just bringing attention to it. It is at the bottom of brooch so when it is pinned on, you can't really notice it. I'm not to sure it can be seen in the pictures. 1" Jewels1-1 checked