“There’s dance all over the world, and many different forms, and great ones,” the New York City Ballet star Jacques d’Amboise says in the PNB online film Jewels at 50: Pacific Northwest Ballet. “Only ballet is the dance human beings invented to try to belong to the air, off the ground, out of the ordinary.” Here is one of the greatest ballets of all, George Balanchine’s Jewels. Its three acts—“Emeralds,” “Rubies,” and “Diamonds”—provide three takes on classical style, respectively French, American, and Russian. But more than that, it’s a tapestry interwoven with allusions to ballet’s ondines, firebirds, swans, and steeds—there’s even a unicorn. Jewels is a glittering bestiary of romantic love. —L.J.