Lincoln Kirstein called it a “full-length ballet without a plot,” but George Balanchine’s Jewels—which premiered in 1967 and consists of three movements—is a castle keep of medieval imagery, Symbolist echoes, neoclassical refractions, and the story of Balanchine’s heart. Some look to it as a primer on national approaches to classical dancing: the deep lustre of French “Emeralds,” the elbowing refractions of American “Rubies,” and the cosmic grandeur of Russian “Diamonds.” I like to think of it as a tapestry interwoven with allusions to the ondines, firebirds, swans, and steeds of ballet. In “Diamonds” there’s even a unicorn! (Balanchine loved the Cluny tapestries in Paris and was familiar with the Unicorn Tapestries at the Cloisters in upper Manhattan.) Jewels is a glittering bestiary of romantic love, and the gems are the ballerinas who dance it. —Laura Jacobs