At some point I decided to add different types of walls in Wizard's Quest.
Just to make progress visible, and to add some variety.
First decision was simple: starting from first levels with undead enemies walls are moldy.
On next set of floors there were no enemies with some specific trait.
So I came up with 'wet' walls. Not so uncommon in mines.
Along with wet walls there are puddles.
After wet walls there are walls ... covered with fluorescent mushrooms
You can see the wall itself in darkness, but not the floor near it.
And than ... I ran out of ideas.
I have 3 main colors left: red, yellow and purple.
Red color I reserve for bloody walls of final level.
So, yellow or purple.
Sandstone can be yellow, but it's not very common as a walls material in mine. AFAIK.
Purple... mb walls covered with mystic runes or something like this.
And some random special effects when player is wondering around. Horror style.
Can't decide.
Any good ideas?