Rainbow shells not spawning?

[Sure, Not]

I am on year 2 summer, sold all my rainbow shells before and now I need 1 for Qi quest and I've been checking beach every day its Summer 20th now and 0 shells, whats up?

[Keeper Of Monsters]

It's RNG, so - you just got unlucky.
Maybe you will get one in the last week (hopefully).
But even if not - you can still get it from Demetrius in the mail - if you get a mail from him (then jsut reload the day until you have that shell and not something else that he sends).

[Demethrite]

To me they seem more common during winter.

[76561198228000512]

I had better luck getting them from rainbow trout fish ponds (it's RNG reliant too, but you got a chance year-round)

[Snuptik]

you can get them in mines too. i got mine for the quest in it.