Always upvote Terry Pratchett, especially The Wee Free Men, the best bedtime story ever. (And it doesn't matter that I mangled the accent, pronouncing Crivens! with a long I. I got the energy right. Besides, Feegles run on Narrativium, free of Roundworld constraints.)

The article refers to the gold and silver particles acting like a rainbow. Rainbows are simple science and yet they're also magical, every time.