You need the blackmetal pickaxe to obtain Black Marble, but you can use a Soldier to smash some, or a stonecutter to demolish an existing structure.

It's definitely possible, but not only is it going to suck massive amounts of ass to go into the mistlands without the wisplight, as ineffectual as it ends up being, it's still better than blind, fighting through an infested mines with Iron Tier weapons is wildly inadvisable.

If you are even able to accomplish the feat, you would have rendered it pointless anyway. With such skill as would be required, you certainly wouldn't need to trouble yourself with any of the mistlands tech.