I found some "ex jewlery" coins online and I'm just wondering what the difference is between these coins and regular coins and if their value is diminished?
It all depends. If they are gold/silver cleaned or not. From the pics I see, I think they are fake. Pictures will always help us determine value.
For bullion coins the value is gold weight, so as long as there aren't parts of the coin missing the value will not be affected much. If it's a coin with a collectible premium, having been mounted will erase much or all of that premium. Really depends on the coin, how significant the damage is and the sharpness of the details.
If they are genuine they are the same as "regular" coins except they have been used in jewelry. They may have damage from being soldered to the jewelry piece or they may have damage from being in a bezel. They may have been polished. They may have excessive wear or damage (e.g., the $10 Liberty gold coin my cousin has in a ring - the obverse gets a ton of wear and damage but the reverse is protected). Most ex-jewelry coins are worth less than similar coins that were not used in jewelry - sometimes a LOT less.
Common date damaged coin. Basically being sold for melt, as it should be. edit - something worthy of note. Generic gold coins, even those graded as high as MS63, are currently being sold at melt values.
