Create your own customized Gem Bar necklace collection in our many sizes and colors! 16" is a S/M size and 18" is a M/L size . model in photo is wearing a 16" apatite in gold fill. Gems are authentic and findings (chain, clasps, etc) are all 100% hypoallergenic, non tarnish, Sterling Silver (925) and 14K Gold Fill (does not rub off or tarnish over time). These necklaces are high quality and stand up to daily wear, layer well with some of our pendant necklaces, shields, or wear alone!