Bright Purple
It's about the aquifer Pebbles and Moon were built on. Iterators are generally built on top of these sources of water.
I admit I was quite jealous of it, as mine is way smaller and contaminated by sulfur from the local Living Rock wellspring.
Running deeper algorithms was hard at first, especially when you're dealing with sulfur-eating microbial colonies saturating your memory conflux!
But eventually, water vapor became so common it wasn't an issue anymore.
And concerning the microbes, I have come to make peace with them. They come and go periodically.
They still have a tendency to affect my mood, but I have no idea why.