If you want to see what your coin would look like without the clasp, see some examples on this Wildwinds page
; scroll down to the entries around "Lyons RIC VII 254".
These clasps almost always do damage the coin, unless the jeweller has been very, very careful and the jewellery-piece hasn't been worn very much. The coin will likely suffer further damage if removal was attempted. As such, it is worth far more as an intact jwellery-piece than as a damaged coin and a lump of scrap gold and unidentified gemstones. Coin collectors, however, would probably not appreciate owning such a piece.
I am wondering why someone would enframe a coin of Constantine II though. Perhaps a previous owner had mistaken it for a coin of his much much more famous - and much more likely to be revered - father; Constantine the Great is a Saint in the Orthodox church.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis