The mystery coins might not be actual coins, but rather coin-like items specifically made for use in jewellery like this. SO they may be blurry and indistinct not because of the photograph, but because the actual coins are blurry and indistinct. Notice how the bottom row of coins are held onto the chain with clamps, but the top row of coins have soldered loops at top and bottom.
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