"I wasn't sure initially if the diamond synthesis would scale around diamond dust used as seed crystals, so I also got thirty-two jewelry-quality diamonds, the sort that are unusually clear but too small for even a Limited Wish, and had those polished smooth and spherical, and Prestidigitated them before throwing them in, to try to ensure that early diamond deposition would be very regular for at least the next hour... anyways, I don't know if that worked, but only three times, or it was just some unrelated seed that went really well... anyways, I ended up with three of these."
Keltham takes from his Bag of Holding three exceptionally clear unfaceted jewels, barely small enough that you could close your fist all the way around one of them.