CHAIN NECKLACES—like those actress and model Marisa Berenson layered so effusively in 1969—have never exactly been out of style. Dating back to at least the Roman era, simple links have been the basis for trends from the Belle Époque to the early 2000s, when they resurfaced as Carrie Bradshaw-style nameplate necklaces. Most recently, fashionable sorts are embracing distinctly chunky gold versions. Tiffany & Co.’s HardWear collection, a love affair with weighty links, was introduced in 2017. On 1stdibs, the online luxury design marketplace, sales of gold chain necklaces were up 80% this August compared with last; there, you can find dozens of substantial chains like the ones Jackie favored as she transitioned in the late ’60s and ’70s from a restrained Kennedy to a blingier Onassis. “The ’70s were a decade of expression and women’s rights and there are some political and social forces that are echoing that today,” said Cristina Miller, chief commercial officer of 1stdibs, speculating on the gold chain necklace’s comeback. The latest additions to the chain-necklace canon come from French luxury house Hermès, whose new jewelry collection riffs on iconic links. The chain is “suc...