Hmm… not sure if I should submit this question to Cecil or not, so I’m posting it here first.
In the play and movie Deathtrap , Clifford refers to Sidney’s “seventeen-jewel brain.” And in their song “Six-Man Band,” the Association sing “We’ve got the seventeen jewels that dictate the rules.”
OK, what are the seventeen jewels, and where does this reference come from?
Thanks a-mightily… 
– The Histrion:
The reference is to watches - “Both mechanical and quartz analog movements often incorporate jewels, round bearings used to decrease friction between moving parts.” More expensive watches use more jewels, so a seventeen jewel movement would be (supposedly) superior to a seven jewel movement.
Watches. Mechanical watches used to have jewels in them, used for low friction in parts sliding against each other. It was generally thought that the more jewels the better, and so more implied higher quality. Wasn’t always the case, though.
So the “seventeen-jewel brain” means high quality - smart and creative.
The other reference might mean jewels in a crown. Not sure about that one.