On a narrow cobbled thoroughfare in this small Tuscan city, one shop’s windows glimmer with jewelry created over centuries. Gioielleria Carli, founded in 1655, promotes itself as Italy’s oldest jewelry store.

Hanging from its rib-vaulted ceilings, hand-painted in plaids and fleur-de-lis, crystal chandeliers illuminate a museum-worthy exhibition of antique jewels and silver tableware. But the precious pieces are all for sale.