Crafted from 18k yellow gold, this vintage 20 inch Mariner chain style necklace is a timeless piece of fine jewelry. Each link crafted perfectly . The links measure flat 1mm and wide 3.5mm. It weighs 28.90 grams and has a round spring clasp.  

.It is signed on the spring clasp and also on the chain tag 750. It is hallmarked  balestra and 13VI. A necklace by Giovanni  Balestra & Figli. I would date this necklace about the late 1970s to early 1980s. In excellent vintage condition.