re: Melting gold coins to make jewelry (not sure if right board or not)

Fist check at a gold or coin shop to see if the coin has a collector value greater than the gold value. That same shop can sell you a mounting to make the coin a pendant.

If you still want to melt it down, then find a jeweler in your area who casts pendants, rings, etc. using lost wax method. They can either carve a custom item in wax or let you pick something from a catalog. If hardness of the gold is an issue, a lower carat weight gold alloy can be added when the coin is melted.