This "Sliding" suite of necklace, bracelet and half hoop clip earrings of diamonds and 18K gold by the Parisian firm of René Boivin dates from circa 1975. The torque necklace and hinged bangle are each mounted with four polished bombé slides that shift along the matte sections to reveal fields of pavé-set round brilliant-cut diamonds, and the half hoop earrings are ensuite. An ingenious design of "dual identity" by Jacques Bernard, this Boivin creation of superlative workmanship is a late example of the maison's much sought-after streamlined and timeless jewelry.