So I found this weird ore in the crimson tunnels, and I couldn't mine it at all, even with a cobalt pickaxe. No explosives worked, and the block wasn't listed on the wiki.

Anyone know what it is? And how to mine it?

2 Answers

That looks like Titanium Ore. You can mine it with a Mythril or Orichalcum Pickaxe or Drill.

If you press M to bring up the fullscreen map, you can hover your mouse over a block to find out what it is.

It's Titanium, the alternate version of Admantite Ore. You can mine it with a Mythril or Orichalcum drill.

It should be on the wiki.