When it comes to diamond rings, one carat is among the most popular weights chosen for the center stone. To many people, however, this is just a number, and they don’t really know how large such a diamond looks.
Let’s take a closer look at the actual size of a one-carat diamond and see how big it looks when put on the hand, in a ring’s setting.
How Big Is a One-Carat Diamond?
Carat is a measure of weight, and one carat is equal to 200 milligrams, or 0.2 grams.
How big a one-carat diamond looks will depend on its dimensions.
These dimensions, in turn, depend on the cut of the stone.
Let’s take a look at the approximate measurements a one-carat stone has depending on its cut:
- Round cut: around 6.5 mm in diameter
- Square princess cut and Asscher cut: approx. 5.5 mm long on the side
- Emerald cut (rectangular): around 6.5 mm long by 5 mm wide (these sides can vary)
- Radiant cut and cushion cut: approx. 6.0-6.5 mm by 5.0-5.5 mm
- Oval cut and pear cut: around 8.0-8.5 mm in length and 5.0-5.5 mm in width
- Marquise cut: approx. 10 mm long and around 5 mm wide
Keep in mind that all these figures are approximate and actual size can vary depending on the proportions of the particular stone.
How to Make a Diamond in a Ring Look Bigger
There are several factors that affect how big a diamond looks when mounted in a ring: the type of setting, the stone’s cut, and its shape.
How the Ring Setting Affects Diamond Size
Some ring settings leave more of the diamond visible compared with others.
For example, prong settings do not cover as much of the stone’s surface as bezel or channel settings.
A mounting that holds a diamond with four or six prongs can be a good choice if you want to show off as much of your stone as possible and make it look bigger.
Diamond Shape and Its Impact on Size
Some diamond shapes tend to look bigger than others, even if they are of the same carat weight.
If you want to create the illusion of size, look for shapes that are wider as opposed to ones that are long and thin. For example, a square Asscher-cut stone will look bigger than a narrow marquise-cut diamond.
When it comes to the appearance of size, shape doesn’t tell the whole story, however.
Sometimes, the way a diamond is cut can make it look smaller even though its shape looks wide and square. This is why you have to also consider the importance of cut.
Cut as a Factor in Diamond Size
The way a diamond is cut can greatly affect how big it looks. In general, cuts that are designed so that they are deeper tend to look smaller compared with shallower cuts, assuming the stones being compared have the same carat weight.
For example, the princess cut has more depth compared with the emerald cut.
In general, if you want a diamond whose surface looks larger when set in a ring, look for stones that are cut shallow.
Don’t forget, however, that each cut has certain ideal proportions, and if the depth of the diamond you buy deviates dramatically from the standard for the particular cut, the brilliance of the stone may be diminished.
This is particularly true of brilliant cuts such as the round cut.
Diamond Size and the Size of the Fingers
Finally, don’t forget to consider the hand of the wearer when selecting size for a diamond in a ring.
Wider fingers can make a diamond look smaller than it would appear if put on a hand with slimmer fingers.
Also, consider the fact that more elongated diamond shapes make the fingers look longer, while wider shapes accentuate the width of the hand.
Where to Buy a Diamond Ring?
For diamond rings, we highly recommend James Allen (read our review) because it shows real photos and videos for each diamond so you can take a 360-degree look at any stone before having it set in a ring.
For colored diamonds, we recommend Leibish & Co., which specializes in fancy color diamonds (use code JewelryNotes200 at checkout to get a 5% discount).
Also read our Diamond Buying Guide and check out our selection of eye-clean diamonds that we've vetted for quality.