But you just fuckin said the point of a black blade is hardness lmfao and when zoro makes them black they are harder. Go lie down.
Seems you're confused.
I said a Black blade simply means hardness.
When Mihawk says any blade can become black, he's just saying any blade can become hard because you know:
- Haki makes things hard.
What you don't seem to grasp is Invisible Armament and Black shaded Haki are both invisibe, the black is simply harder. If you don't know this, then you've not been reading this manga astutely. Everyone should know this.
When a blade has any form of the invisible Haki (whether it's the relatively weaker invisible Haki or the black shaded invisible haki), both make things harder, thus being black blades in essence and not literally.