Terraria – this ore, and why can’t I mine it

There are several problems with hell and several ways to overcome them.

Hellstone

• Wearing an Obsidian skull will stop you being bunt from standing on it.
• Putting sand on top of the block before mining will remove the lava that is created.
• The buildings in hell give an excellent vantage point for mining the hellstone through the wall.

Lava

• Rocket boots allow you to cross large lava lakes easily, they are sold by the npc Goblin Tinkerer.
• Grappling hooks or Ivy whips work in similar ways.
• Placing sand above the lava will remove it when the sand falls into it, but you have to build up from the bottom.
• Water walking potions also allow you to walk on lava without being hurt.
• There is a trick with flippers that allow you to swim above the lava.

What you've got there is Crimstone, not Crimtane. You'll need a Nightmare or Deathbringer pick to mine that.

You could also use explosives, or Purification Powder will turn it into normal stone.