Regular

“You are aware of the concept of metamorphorical rock?”
“You mean the way trolls look like certain types of rock?”
“Indeed. Schist, Mica, Shale, and so on. Even Brick, poor young Brick. No one knows why this is, and they have expended thousands of words in saying so. Oh, to hell with it, as you would say. You deserve a glimpse. Protect your eyes. I, Mister Vimes–”
A black-robed arm was extended, a black-velvet glove removed. Vimes shut his eyes in time, but the inside of his lids blazed red.
“–am diamond,” said Mr. Shine.

– MR. SHINE! HIM DIAMOND! |
Terry Pratchett, Thud!