Do ores all spawn as a 'set'?

With v1.2 there are several alternate ores available. With every world generation only one of each below 7 pairs will be available (i.e. if the world contains Tin then it will not contain Copper etc.) :-

Tin / Copper
Iron / Lead
Tungsten / Silver
Gold / Platinum
Palladium / Cobalt
Orichalcum / Mythril
Titanium / Adamantite

So my question is, do the ores spawn as a 'set' i.e. if the world contains Tin, would it also always contain Iron, Tungsten, Gold, Palladium ... etc.? Or does every ore type have a 50/50 chance to be one or the other?

Reason I ask is because I want to collect all armor types and I want to know roughly how many worlds I need to generate to find all the ore types (esp. hardmode ores)


Solution 1:

I couldn't find anything on the wiki that states this, but on my two personal worlds, I have ores from each "set". For example, I have:

  • Tin
  • Iron
  • Tungsten
  • Platinum
  • Orichalum
  • Titanium

in one world, but in the other world, I have:

  • Copper
  • Iron
  • Silver
  • Gold
  • Palladium
  • Orichalum
  • Adamantite

So it is probable that it is a 50/50 chance that you will get one ore or its variant for each ore.

Solution 2:

In this other wiki page the following paragraph can be found:

Each hardmode ore is chosen at the moment you break the first three altars in the world. You can choose the ores you like by quitting your world without saving (by ending the task or killing the process) after smashing your first altars. It is easier done with a server.

Which tends to indicate that the hardmode ores are not "linked" together (and - more interestingly - that they can be chosen, which limits the number of world to generate in order to cover the whole ore spectrum); this is coherent with the examples provided by NovaSword, where one world contains Orichalcum and Titanium, and the second one contains Orichalcum and Adamantite (as tier 2 and 3 hardmode ores).