Half Moon Cut: Side or Main Stone?

Close up of a first quarter moon (half moon) with different details on its surface (craters, mountains, etc.) visible.

Diamonds are glamorous and are a wonderful centerpiece for any engagement ring, but did you know that some diamonds can act as an accessory for your accessory? One of the most common diamond cuts for this purpose is the half-moon design. This night-named cut will look great on your wedding day and even better throughout your marriage.

What is a half-moon diamond?

It’s exactly what it sounds like, the gem is shaped like a half-circle. Half-moons are typically not the only gem on a wedding ring, they are usually beside other gems or surrounded by smaller diamonds. Sometimes two identical half-moon stones are used on the same ring. In this case, the jewelers may place small jewels or a strip of gold or silver between them. Half-moons are also called demilunes, but no matter what you call them, be sure to get a good one.

How do I shop for this cut?

Mazal Diamond says that ideal length to width ratio is 2 – 1 or 2 – 1:75 for a wider gem. The Diamond Source of Virginia says to watch the cut too, a badly cut half-moon may have a “bow tie dark shadow.” The properly cut ones have a polished gleam. When in doubt, follow the Gemological Institute of America’s Four C’s: Cut (style/shape), Color, Carat (stone’s weight), and Clarity (clearness, absence of inclusions or scratches). If the rock does well in each of these areas (well-cut, desirable color, reasonable weight, and little to no dents, air bubbles or sand grains in the stone), then it’s proposal-worthy. Demilunes are a beautiful and unique cut, and there are many ways to have at least one on your wedding ring.

Ideal Styles


Simple Bezel

(Half Moon Diamond Ring, Simple Engagement Ring, Crescent Moon Ring, Boho Engagement Ring, Diamond Moon Ring, 0.25 Carat Diamond Ring, sold by artemer on etsy.com)

This single-jewel design is simple but provides an understated beauty. The unadorned bezel will look great with both formal and casual wear and a white diamond will go great with any metal. However, we understand that less isn’t always more.


Jewel Frame

(HALF MOON DIAMOND RING, ROSE GOLD DIAMOND SET available on capucinne.com)

The last pic might be too plain for some folks, we get it. The extra diamonds add some elegance to an otherwise plain ring. As lovely as this photo is, it still may not be enough for some wearers.


Side stone with gem between

(Sapphire and Half-Moon Shaped Diamond Ring, available on Bluenile.com)

This Blue Nile Ring features a bold sapphire between two beautiful half-moon diamonds. A ring like this follows and breaks tradition. It has a sapphire, which is not the typical wedding gem, and two diamonds, the jewel most commonly associated with marriage. Also, the contrast of the white diamonds and blue sapphire is gorgeous. 

The only thing better than diamonds is diamonds on top of diamonds. Better yet, these demilunes pair well with other gems. True, the half-moon cut looks great by itself too, but we’re never against more diamonds on jewelry.