In old alchemical lore, each planet corresponds to a metal

Sun = Gold
Moon = Silver
Sun/Moon = Platinum
Mars = Iron
Venus = Copper
Saturn = Lead
Jupiter = tin

For planets more recently discovered, it is not clear whether it should be

Neptune = cobalt
Uranus = bismuth

It's interesting to find echoes - for example, the flag of Chile shows Venus. Chile is also rich in copper.

Comments welcome.