I'd rather go for "Glitterrain" or "Rain of Glitter". But it depends on what you want to express / put your emphasis on. Language isn't the most precise thing.
Yes, you are right. I only mentioned it because I am from Germany and noticed this. Since the MC later explains how he means it, I added the edit sentence later.
I only have thought about how to translate it in a kind of literal sense and not in the way someone could express it without losing the original meaning of the German word.