Green’s Dictionary of Slang

(US prison) handcuffs, shackles, chains; thus jewel room n., the manacle room in a prison.

1873		J. O’Connor Wanderings of a Vagabond 293: ‘Put the darbies on the kid,’ drawled out the lieutenant to one of his subordinates, and in a moment more I was adorned with a portion of the jewelry belonging to the city.
1927		‘Jargon of the Und.’ in DN V 451: Jewelry, Handcuffs.
1935		A.J. Pollock Und. Speaks n.p.: Jewel room, the manacle room in prison.
1949		Monteleone Criminal Sl. (rev. edn).