What do you mean? I feel like brown contrasts pretty well with gray.
I mean, sure, with admin approval, this could be added, but it seems like a stone mountain would make the chest easier. And with large areas being stone, it would limit where chests could spawn by a lot.
~ @cdhoff
Supply drop chests, no matter if they spawn on stone or not, appear as a stone block until you get close to them (due to the anti-xray plugin).
I do see how it would limit where chests could spawn, but it's discouraging to run a long distance to the supply chest just to find that the chest is camouflaged as stone within a mountain of stone, making it very difficult to find it.