A pendant gives you one point of light at the center of your neckline; a riviera spreads light all the way around it. That changes how you wear it. A pendant works under a collar or over a sweater, while a full line is meant to be seen and pairs best with open necklines, from a scoop neck top to an evening dress.
It also changes what you are buying. Instead of one important diamond, you are paying for many smaller ones that need to match each other, plus the links and the clasp that hold them together. Workmanship counts here more than on almost any other necklace.
Prong set lines show the most sparkle, because each diamond sits in a small claw of metal that lets light in from the sides. Bezel set lines wrap every stone in a thin rim of metal, so they lie smoother against skin and catch less on hair and knitwear, with slightly less light in return.
Think about where it will be worn. For evenings and events, prongs give the brightest effect. For a necklace you want to wear with scarves, high collars and the occasional sweater, a bezel line is easier to live with.
Length decides whether the diamonds hug the base of your neck or fall in a softer curve. A 16 inch necklace usually rests around the collarbone, 18 inches lands just below it, and 20 inches sits a little lower. Neck size shifts all of this, so the easiest test is to lay a piece of string where you want the line to fall, then measure the string.
Check the stated length on the product before you order. If you plan to wear the riviera with a pendant on a separate chain, leave a clear gap between the two lengths so the stones do not rub.
The carat figure on this kind of necklace is total carat weight: the sum of every diamond in the line, not the size of any single stone. Two necklaces with the same total can look quite different, since one may use many tiny diamonds and the other fewer, larger ones. Decide whether you want a fine glittering thread or bold stones you can count from across the table.
Matching matters as much as weight. In a well made line, the diamonds are close in size and color, so no stone looks brighter or warmer than its neighbors. Pair it with matching tennis bracelets for a set, or look at lab grown diamond necklaces if you want more weight for your budget, since lab grown stones cost far less than natural ones of the same size and grade. Every Rare Carat order ships free and insured, which is reassuring on a piece with this many stones.