Alright, so I've been meaning to write out a planet with golden/yellow fields and a violet / purple ocean.
What I was thinking about is having the water of this world is so clean and nourishing that its very color is violet, as a sort of representation of its alkaline nature. I was thinking a possible explanation, taking from the real world from the likes of Rio da Prata in Brazil and many others where the water is so filtered and clean, it's crystalline in appearance. Anyway, I'm not sure if the same reason as to why a water would be clear would work to explain why it's purple.
The thing I'm mainly going for is that this ocean is clean. Maybe it doesn't have to be H2O per se, but that it serves the same purpose, at the very least to the local species (which I was hoping would be human, but if that's not possible, I'll have to deal with it.) Perhaps a high concentration of certain minerals and calcium carbonates could go about into explaining this 'phenomenon?'
I think I once heard about microbes and/or marine life that purify the water by emitting some sort of radiance of some property, but I've been trying to fact-check if that was something real or not, and I couldn't find anything. If that's just something I daydreamed, could that suffice as a valid reasoning? Maybe creatures unique to the planet, not necessarily microbes that do so, and such high quantity in these alien lifeforms have allowed the oceans to turn violet?