While shopping for diamonds, one challenge that most jewelry buyers face pertains to the ideal carat weight. To better understand the best course of action, it is important to start from the beginning.

Carat refers to a unit of measurement for diamond weights; one carat equals 0.2g. Here, distinguishing between carat and karat is necessary since these terms are common in the jewelry industry. Carat is almost exclusively used in the diamond trade, while karat is widely used in the gold trade. Karat refers to the purity score of a piece of gold or gold jewelry. To put it into perspective, a 24-Karat ring is a ring made up of almost 100% gold. An 18-Karat ring comprises 18-parts gold, with the other six parts consisting of a different metal or metals.

For some diamond shoppers, carat differences do not mean much if the other three aspects of the Four Cs—cut, clarity, and color—have been taken care of. However, experts recommend researching widely on the right diamond carat before investing in the stone.

Carat variations reflect on the overall price of a diamond; the higher the carat weight, the costlier the gem. But more importantly, a diamond carat impacts the beauty of the stone. So, how big is a one-carat diamond, and how to choose the most appropriate one?

How Big Is a One-carat Diamond?

0.2 grams may not look or sound heavy, probably equivalent to the weight of an average raindrop or a quarter of a raisin. But in the diamond industry, numbers mean a lot. As already mentioned, a slight variance in carat comes with significant price variations, ceteris paribus. How big a one-carat diamond looks depends on various aspects some of which have been explained as follows:

The Diamond Cut

The size of a one-carat diamond significantly depends on the cut. For clarity purposes, the words “cut” and “shape” have been used interchangeably under this section, though the shape is one of the elements of a diamond cut.

A one-carat round brilliant diamond has a width of 6.5 mm. This is reasonably big, though not as big as the oval, pear, or marquise cuts of similar weight. A one-carat oval cut diamond measures around 7.55 by 5.54mm. As for marquise cuts, one-carat comes to roughly 10mm x 4.75mm. Depending on where the diamond is set, the marquise and oval shapes will look bigger than the brilliant round shape. The marquise, pear, and oval diamond cuts are known for their impressive illusions of size and are therefore ideal for customers looking for something that appears larger without necessarily investing in extra carats.

On the other hand, some diamond shapes appear small even with higher carat weights—the Asscher cut is a perfect example here. When polishing Asscher diamonds, cutters place more emphasis on its surface area, which explains why Asscher cuts have the largest surface area.

The following table gives an overview of the size of a one-carat diamond across popular cuts:

Diamond Cut	DIMENSIONS
Round Brilliant Cut	6.5×6.5mm
Emerald Cut	6.68×4.95mm
Princess Cut	5.51×5.51mm
Marquise Cut	10.38×5.19mm
Heart-shaped Diamonds	6.56×6.56mm
Asscher Cut	5.61×5.61mm
Trillion Diamonds	7.74×7.74mm
Pear-shaped Cuts	9.05×5.45mm
Radiant Cuts	5.78×5.78mm
Oval Cuts	8.12×5.41mm

When shopping for a one-carat diamond, it is likely to come across the term “spread” that refers to the size in relation to the carat weight. Therefore, the marquise and oval shapes tend to be more “spready”.

Generally, the size of a one-carat diamond can be enhanced by choosing fancier shapes. Avoid cushion-cut diamonds since they tend to be deep-set due to which factor much of their weight is hidden underneath their surface, making them look relatively small.

However, it is not easy to tell a one-carat diamond from, say, a 1.5 carat one, especially if the diamonds look similar in all other aspects. It does not matter whether one is viewing the stone online or in physical displays, their best bet would be to rely on a diamond certification from a reputable lab.

The Setting in a Ring

The size of a one-carat diamond also depends on how the diamond is set in a ring. For instance, a one-carat diamond will look larger on a platinum band because the white color of the band will reflect the diamond, thereby enhancing its size.

Still, on the setting, always insist on thinner bands; for they are remarkable in accentuating the size of the gem.

Halo ring settings are also preferable for those looking to enhance the size of their one-carat diamonds. In a halo setting, the diamond is the center gemstone surrounded by a ring of micro-pavé diamonds. The paves are included to enhance the size of the center diamond.

But what if a buyer thinks that the one-carat diamond that they have selected looks way larger than they desire? There is no need to worry as they can experiment with some settings to diminish its size. For instance, a bezel setting is known to make diamonds look smaller than they are. In bezel settings, the diamond in the metal edging is surrounded. These are popular for enhancing the shape of a diamond and not necessarily its size. The apparent absence of accent stones makes the diamond look even smaller.

However, there are numerous ways of enhancing the size of a one-carat diamond in a bezel setting. Most notably, one can choose fewer or more slender prongs to hold the stone in place to maximize the surface of the diamond that shows, thereby making it appear bigger.

Diamond Color

Color psychologists are of the view that brighter colors tend to create an illusion of space; the same principle holds for diamonds. Yellow, blue, green, and soft pink diamonds often appear bigger. Generally, insist on colors that reflect maximum light from all the edges of the diamond.

Color also goes hand in hand with clarity. If a one-carat diamond has visible flaws, the blemishes will reduce its ability to absorb and reflect light. Therefore, the diamond may look smaller than it is.

How Much Does a 1-Carat Diamond Cost?

There is no definite answer to this question since several factors dictate the price of diamonds. Also, diamond prices do not increase linearly; instead, they increase exponentially. Therefore, one cannot expect the price of a 1-carat diamond to be half that of a 2-carat diamond, even if other factors remain constant.

Cuts and shapes also determine the price of diamonds. Generally, the round brilliant cuts are the most expensive. The cushion and princess cuts follow closely, with marquise shapes being cheaper.

Colors and clarity ratings are other factors that influence the price of a one-carat diamond. Red and white diamonds are the most expensive. Those who go for red diamonds are often driven by the fancy appearance while those who opt for white are perfectionists looking for a flawless stone.

According to statistics, a high percentage of diamond shoppers prefer the 1-carat diamond, which factor alone affects the stone’s overall cost.

A one-carat diamond may not look too big on screen, one reason why one can only appreciate its size when buying it. However, it is possible to enlarge or diminish the size of a one-carat diamond without necessarily reducing its carat weight. It all comes down to how one plays around with the other aspects of the Four Cs.