These are needed for entry to the final area of the Moon Temple...5 gold coins and 2 iron marks iirc to open a series of locked doors. I have one and have used it, but I can't for the life of me remember if I have put the other one down somewhere or if I am just yet to discover it. Are they an item specific to the Moon Temple or can they be found elsewhere?

Many thanks in advance!

There's an old guide here that may help.