The Jewel Box, strictly speaking, is not an opera by Mozart. Indeed, one could well imagine Mozart objecting to the notion of a pastiche consisting of arias and ensembles he dashed off to showcase famous singers of his time. And he might have even balked at the inclusion of pieces from his abandoned projects. Yet Mozart is Mozart, and some of these stand-alone arias are gorgeous. Now, thanks to New Yorker music critic Paul Griffiths, a clever, felicitous narrative has been concocted as an excuse to string together 26 of Mozart’s assorted operatic ditties. The Jewel Box premiered in New York in 1991 for the bicentennial of the composer’s death. At its center is a character named the Composer, who must come up with an opera to employ several dramatic archetypes, all the while negotiating between the demands of a conniving doctor and a plain man named Pantalone (a Pirandellian conceit, to be sure–perhaps determined by the fact that Griffiths’s plot itself is tailored from materials already written). For this production Chicago Opera Theater has called on Court Theatre’s Charles Newell to make his operatic directing debut. The cast boasts two sopranos well-known to local operagoers: Kimberly Jones (in the trouser role of the Composer), a recent graduate of Lyric Opera’s Center for American Artists, and Sunny Joy Langton (as Columbina, the object of his pursuit), a veteran who teaches at Northwestern. Also featured are Keith Brautigam (Pantalone), Warren Moulton (Doctor), William Watson, and Kurt Link. Friday, 7:30 PM, Sunday, 3 PM, and Thursday and next Saturday, June 22, 7:30 PM, Merle Reskin Theatre, 60 E. Balbo; 292-7578. TED SHEN