I asked my rav my question on Noach yesterday, and he pointed me to a fascinating Ya’aros Devash where R’ Yonosson Eibeschitz says that the Keshes in Parshas Noach is in fact a different type of rainbow. It is a rainbow completely of Techeiless color. And as a reminder, the word Techeiless is of the same root word as Kalei (destroy/destruction), which is what HKB”H would do to the world if not for this Bris HaKeshes.
My only problem is with this is, which I only thought about later on, is why then do we recite a brocho on our colorful rainbow that we see if it isn’t the authentic ??? of the Bris HaKeshes?
Out of curiousity, I googled ‘different types of rainbows’ and came up with a few different kinds, but none was a blue/green rainbow 🙁