The black spot on the rim above the XIII looks more like a corrosion spot than a casting sprue to me. There seems to be other patches of cleaned-up corrosion (around the POR on obverse and the N of ESPANA on the reverse). Silver shouldn't "corrode" under normal conditions, so perhaps it's fire damage that's been mostly cleaned up, except for a couple of stubborn patches?
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

























