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Carat Weight
Commonly believed to represent a diamond's size, carat actually refers to the weight of a diamond. It owes its name to carob beans, which were once used to measure the weight of precious goods, given their seeds were believed to be of equal weight.

Carat Weight Size

Carat weight was made uniform against the metric system in the early 1900s, and one carat is now equal to 0.20 grams or 0.007 ounces. Diamonds that weigh less than one carat can be measured in points; for example, if one carat is equal to 100 points, a 0.5-carat diamond is considered a 50-point diamond.

Generally, the greater a diamond's carat weight the larger its size; however, a diamond gains weight faster than it grows in diameter. While this difference is inconsequential when dealing with small diamonds, which generally have sizes to match their weight, as diamonds get heavier, their sizes can begin to vary.

It's easy to understand why large-carat diamonds are so expensive – as diamonds are cut they lose around 50 per cent of their body weight, and only one in around every one million diamonds mined can produce a fully cut one-carat diamond.

0.05 Carat
2.5 mm
0.10 Carat
3.0 mm
0.20 Carat
3.8 mm
0.25 Carat
4.1 mm
0.30 Carat
4.5 mm
0.40 Carat
4.8 mm
0.50 Carat
5.2 mm
0.70 Carat
5.8 mm
1.0 Carat
6.5 mm
1.25 Carat
6.9 mm
1.50 Carat
7.4 mm
2.0 Carat
8.2 mm

Choosing Carat Weight

There are many factors that can influence how you choose the carat weight of your diamond. First, it's a good idea to determine your priorities in terms of carat, cut, clarity and colour, and what you are prepared to compromise on to achieve the carat weight you want. For example, purchasing an antique-style diamond in a larger carat will sharply reduce its radiance. Conversely, some cuts with smaller carats will shine brightly and create an illusion of a larger stone. Setting can also make a difference – diamonds set with high or tall prongs may appear larger than they actually are, as can diamonds with long shapes (unless its length is buried in a deep setting). Surrounding the diamond with several smaller stones is also a popular way of generating a seemingly larger and more brilliant effect. For those wanting a larger stone than they can afford, finding a diamond with a smaller carat, but a high grade of cut and a brilliant shape, may be a fair compromise, as its brightness and radiance will likely make the stone look larger than it is. Or, you may prefer to simply choose a diamond with a large carat, but lower cut, clarity and colour grades.
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