Green’s Dictionary of Slang

glisten n.

(US) a collective term for diamonds.

[US]‘Ned Buntline’ Mysteries and Miseries of N.Y. I 34: He [...] is as daring a cove as ever cracked a crib, touched a dummy, or palmed a glisten. [Ibid.] IV 46: Let me see – I ’ave two brasslet – real glis’n’s in ’em.