Roberto Coin "Love Letter" Diamond Accent Initial "A" Necklace. 16". Founded in Vicenza, the City of Gold in 1977, Roberto Coin jewelry celebrates the elegance of femininity, creativity and craftsmanship. This classic "Love Letter" piece is a sparkling diamond-accent, block-style letter "A" pendant necklace. Includes cable chain and 2" extender. Lobster clasp, 18kt white gold necklace. Diamond birthstones are the perfect gift for April birthdays.