For one of my projects, I'm developing an inhabited Earth-like world, with the key visual difference being that much of the land is purple, instead of the brownish colour it is on Earth. My question is: how would this be possible?
- The soil must be fertile, and capable of supporting both animal and plant life. I don't mind if it's toxic to humans, as long as it's feasible that life could evolve to be immune to it.
- It has to actually be purple. It can't just look purple (i.e. be covered in something that's purple, or speckled with purple rocks).
- It has to be purple on a permanent basis.
- It has to be purple to a depth of at least several metres.
- The soil needs to plausibly cover a significant proportion of the planet's surface (i.e. the bits not covered by deserts, ice caps, and oceans). So if there's a compound that would result in purple soil, but it would be extremely unlikely to find massive quantities of it on a planet, then that's a no.
- My preference is for a deep, Cadbury's-chocolate-wrapper purple, but if that's not doable, then any shade will do as long as it's visibly purple. Pink does not count.
I am aware of this similar question, and borrowed a few of my constraints from it, but I don't believe it's a duplicate because none of the answers mention purple soil, and blue is not the same as purple.