Disclosure before anything else: the links in this directory are affiliate links, meaning the publication may earn a commission if you buy through them, at no change to your price. It is how a small magazine pays its hosting bill. The entries themselves are written the way the rest of the issue is written, and nothing was included that we would not send a friend to.
What earned each seller its entry: independent grading certificates on center stones, photography or video of the actual stone for sale, a real return window, and sane policies on sizing. The differences between them are a matter of emphasis, noted below.
For sheer selection
Blue Nile
The original large online diamond seller, with an inventory measured in the tens of thousands of certified stones and frequent promotions on settings. The default starting point for comparison, and often the ending point too.
Visit Blue Nile
For comparison shopping
Rare Carat
A marketplace that aggregates stones across many sellers and layers its own checks on top, which makes it the closest thing the industry has to a fare-comparison site. Strongest when you already know your specification and want the sharpest price on it.
Visit Rare Carat
For lab-grown value
Friendly Diamonds
A lab-grown specialist with aggressive pricing and a clean path from loose stone to finished ring. If the arithmetic in our lab-grown essay persuaded you, this is where the arithmetic is friendliest.
Visit Friendly Diamonds
For the setting itself
Keyzar
Known for well-made, current settings at fair prices, paired with lab and natural stones. Worth a look when the frame matters as much to her as the stone, which, per our settings essay, is more often than buyers expect.
Visit Keyzar
Policies change between our readings of them. Confirm the current return window, resize terms, and certificate before paying anyone, including anyone listed here.
The short of it: any of the four will treat you properly. Pick by emphasis: selection, comparison, lab-grown value, or the setting itself.