A ubiquitous NetHack tool of decent utility. Not as good as a wand of digging, but close. Applying a pickaxe in the direction of a diggable wall (most walls are diggable) eliminates that section of wall and sometimes creates a pile of rocks in its place. This is usually the only way to get the luckstone that is at the bottom of the Gnomish Mines. As every dwarf and gnome seems to carry one, you'll rarely have trouble finding a pickaxe.

A precautionary note: when you apply a pickaxe, you will wield it as you do so. You will need to re-wield your preferred weapon when you are finished digging. This leads to the obvious problem that if your pickaxe is inadvertently cursed, you will be stuck wielding it until you can do something about it.

A friend of mine had this problem once. He was making his way back up through Gehennom after securing the Amulet of Yendor when he found himself surrounded by liches, dragons, and other horrible monsters. After some futile combat, he started digging through a nearby wall in an effort to escape. He extricated himself from the melee, only to find that when he tried to wield Mjollnir again, he couldn't -- his pickaxe was welded to his hand! After more futile combat with another group of demons using a cursed pickaxe (it does about 1 damage if you can even hit someone with it), he finally committed suicide. The scoreboard entry:

No Points  Name               	          Hp [max]
.	.	. . .			   .. ..
4  44563   Aardvark-Val-Hum-Fem-Cha died   - [380]
           in Gehennom on level 42. Killed
	   by kicking a wall.

May his soul rest in peace.