The emblem and the coin

"Please Return to Tiffany & Co. New York": from 1966 that line, with a registry number, was stamped on gold key tags, so that whoever found a lost set of keys could send them back through the Fifth Avenue store. A heart-shaped tag on a key ring followed in 1969, and in 1980 the heart became a pendant on a box chain. By the late 1990s the silver tag necklaces had turned an address into a house signature. Tiffany treated its initial the same way in 2014, when Francesca Amfitheatrof built Tiffany T from a gold bracelet with a letter T in the Blue Book of 1975 to 1976.

The older idea came from Rome. Bulgari's logotype swaps the U for a V in reference to ancient Latin inscriptions, and in 1977 the house cut that name twice round the bezel of the Bvlgari Bvlgari watch; the doubled letters later moved onto rings, pendants and bangles. Coins came in the 1960s, when Nicola Bulgari, a grandson of the founder and a collector, revived the Roman habit of setting them in jewelry. Monete keeps two thousand years of wear on each coin inside a heavy gold frame, sometimes hung from a Tubogas choker.

Paris and Milan answered with signs of their own. Jean Dinh Van took 24-carat gold in 1991 and hammered it into a disc after the bi of ancient China, where the disc stands for the sky. Buccellati cut out its house emblem, a four-petalled rosette, for Opera in 2015, the first line it built entirely from that mark.