Each link style has its own look. Cable is the classic: simple round or oval links, light and flexible, the usual choice for hanging a diamond. Box chain uses small square links, so it looks crisp and keeps a hanging stone facing forward. A rope chain twists its links into a spiral that catches light as you move.
The bolder styles are made to stand alone. A Franco chain packs its links tightly into a smooth, heavy line. A Cuban chain lies flat with thick, interlocking links and has the most presence of the group. Paperclip uses long, open links that feel airy and modern, and it layers well with finer gold chains.
Pick the length by where you want the chain to land. At 16 inches it sits around the collarbone, which suits a bare chain with an open neckline. An 18 inch chain falls just below the collarbone and is the length people wear most with a pendant. At 20 inches it drops a little lower and clears a crew neck.
For a layered look, space your chains a couple of lengths apart and put the heaviest link at the bottom, so the finer chains do not slide under it and knot.
If you plan to add a drop now or later, buy the chain with it in mind. It has to pass through the pendant's bail, and a thick Cuban or Franco often will not fit a small one. A slim cable or box chain suits most diamond pendant necklaces and keeps attention on the stone.
Worn bare, the chain becomes the main piece, so size up the link rather than the length. An initial charm is the one addition that rarely fights a bolder chain; see personalized necklaces for that idea.
For gold you never take off, 14K (58.3 percent pure) is the practical choice: it is harder and resists scratches better. 18K gold (75 percent pure) has a deeper, richer color but is softer, so it suits a chain worn with a little more care.
Color is personal. Yellow gold is the classic warm tone, rose gold gets its pink from copper, and white gold is plated with rhodium for its bright finish, which can be replated when it wears. A matching chain bracelet in the same link and color makes an easy set. If this is your first time buying gold online, it may help to know that Rare Carat is rated 5 out of 5 on Google and Trustpilot.