Our local music scene is chock-a-block with worthy programs sporting titles like"Jewels and Discoveries" - and alas, usually a few of the gems in question turn out to be rhinestones.

So imagine my surprise when Boston Baroque's "Jewels and Discoveries" - which only saw two performances, last weekend - turned out to be solid Cartier from start to finish.  Conductor Martin Pearlman pulled together a program of brilliant obscurities, and his orchestra, chorus and soloists polished them to a dazzling sheen.  Tenor Keith Jameson was sidelined due to illness, but he was ably replaced (in Monteverdi's Combattimento di Tancredi e Clorinda) by the talented Aaron Sheehan, and everyone else seemed energized and more precisely on point than they've been in the recent past; or perhaps the difference was that conductor Pearlman, though he kept the pace sprightly (as always), only occasionally broke the usual baroque speed limits.  Whatever the reason, this was Boston Baroque at its finest - which is very, very good indeed.

Or perhaps the difference was simply that the program sparkled so consistently, and the singers and players themselves responded to that quality.  The concert opened with Dietrich Buxtehude's Heut’ triumphieret Gottes Sohn (Today God’s Son triumphs), an Easter cantata of surpassing grace and richness. An introductory sinfonia and fanfare led to a remarkably melodic chorale in which a series of soloists took pride of place - with particularly fine work coming from alto Martin Near and bass-baritone Ulysses Thomas. This was followed by two striking works of Monteverdi, Beatus Vir, a sublime setting of Psalm 112 which Pearlman gave his usual dancing buoyancy, and then what amounted to the centerpiece of the evening, Il combattimento Tancredi e Clorinda, a stunningly dramatic piece based on Torquato Tasso’s epic poem of the Crusades. In this Christianist potboiler, the hero Tancredi challenges a Saracen knight to battle at the gates of Jerusalem, not guessing that "he" is really a "she" (Clorinda, in fact, the woman he loves, surprise surprise!). Can you guess the rest? Probably - although I'm afraid these days we have to wince a bit at the final twist, in which the dying Clorinda, a Muslim, begs her beloved (and unwitting killer) to baptize her. Yuck.

Still, even this questionable bit of Christian triumphalism (Monteverdi was a priest, remember) is rendered with sublime delicacy (indeed, poor Clorinda's death is almost overwhelmingly poignant) and the rest of Tancredi e Clorinda is simply terrific. Monteverdi literally invented the tremolo for the piece (that's right, before Tancredi e Clorinda nobody had ever heard a tremolo), explicitly demanded very precise pizzicatos to convey the thwacks of the lovers' swords, and in general called for a wild dynamic that in its day was thought crazy. And to be honest, battle music really hasn't gotten that much better over the past four centuries - Tancredi e Clorinda still thrills, and the narration is a hoot, with the lovers' vows framed by "he said" and "she said" from the narrator, as if we were simultaneously listening to an opera and watching a silent movie. Both Tancredi and Clorinda were ably embodied by bass Bradford Gleim and soprano Mary Wilson, and Aaron Sheehan, though stepping in at the last moment, made quite the dashing narrator.  (He had to dash, as this was the one time in the program Pearlman's tempo approached a gallop.)

The second half of the concert, though still remarkable, never reached quite the same musical and dramatic peaks.  It opened with sacred music by Heinrich Biber, mixed with two of the same composer's Mystery Sonatas, violin pieces devised to convey the 15 mysteries of the rosary.  The psalm settings and the Agnus Dei Pearlman had selected were lovely (and gave soprano Teresa Wakim,  alto Thea Lobo and tenor Murray Kidd a chance to shine), but it was the sonatas that threw off a strangely  memorable fire.  Each of the 15 is tuned - or "distuned" - in a particular way (which is too complicated to go into here), which gives the instrument an eccentric timbre, and gives the violinist a headache, probably (because of the unusual tuning of the instrument, each piece has its own bizarre key signature, too).  Add to that the fact that both of the sonatas on the program ("The Crucifixion" and "Assumption of the Virgin") seemed fiendishly difficult, and you can imagine the challenge facing concertmaster Christina Day Martinson.  She seemed unfazed by all this, however (but then she never seems fazed), and, working with two separate violins, carried off the sonatas with spirited verve (indeed, the final gigue from the "Assumption" was almost dizzying).

The crowning glory of the program was literally a discovery - an early Gloria by Handel that was only authenticated a few years ago.  To be honest, though very beautiful, the piece almost felt like a bit of an anti-climax after the impressively knotty Mystery Sonatas  - luckily, however, Mary Wilson returned to carry it off. Ms. Wilson's voice is just about perfect for Handel - her tone is ripe with sun, and her phrasings so flexible they seem to almost ripple. By the end of her beguiling performance, any and all sense of anticlimax had been banished.