The Cartier Loop Tiara

Photos (clockwise from top left): Queen Sofia of Spain; the Countess of Barcelona; Doña Simoneta Gómez-Acebo y de Borbón; Infanta Pilar of Spain, Duchess of Badajoz; Queen Sofia of Spain

For a royal family that has faced serious upheaval in the last century, the Borbóns of Spain have managed to hang on to some serious heirloom tiaras. That's been possible in part because the family has largely