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Carat Weight

Content

What is carat weight?
How do I determine the carat weight of a diamond?
Weighing
The carat determination formula
Size to carat table

The modern world is characterized by its pragmatism. Everything in it has a price, so if you want diamonds, the most beautiful stones in the world, you should learn how to evaluate them and determine their real value. And to do that, you need to know what a carat is and how diamonds are measured.

Only a professional jeweler can fully evaluate diamonds using the “4C” system. It is used to determine the value of a stone by color, clarity, cut and carat.

Technically, the grading process itself can be divided into several stages:

Cut quality assessment.
The carat weight of the stone.
Color – from colorless to brown. Jewelers do not give exact specifications here. As a rule, they use the epithets “colorless”, “faint yellow”, “near colorless”, etc.
Clarity – the presence of inclusions, etc. Only after this is the true value of the stone determined.

Only by evaluating a diamond according to these criteria can its true value be determined.

What is carat weight?

A carat is a measure of a gemstone. In ancient times, acacia seeds of Ceratonia siliqua were used to determine a gemstone’s weight. In the early twentieth century, the International Committee of Weights and Measures legalized this unit of weight, the carat, as a measurement for precious stones.

A 1-carat diamond has a cross-section diameter of 0.25 inches (0.64 cm), it weighs 0.2 g or 0.007 ounces, it has 57 facets and a high degree of ray reflection.

Hence the following classification for all diamonds:

The large category includes diamonds weighing one carat or more.
Medium diamonds weigh up to 0.99 carat.
Stones weighing less than 0.29 carat are called small stones.
Small, fine particles or fragments of diamonds are called “diamond dust.”

Large diamonds are rare and seldom sold. Diamonds of large size and weight can only be seen at auctions. Diamonds of 25 carats or more are very rare and have their own names.

Every cut diamond is subject to certification.

Finished stones are listed on the exchange listing and from that moment on the price is determined by the policy of the Diamond Exchange. It is impossible to buy a stone cheaper than the one listed on the Diamond Exchange.

How do I determine the carat weight of a diamond?

There are several ways to determine the carat of a diamond:

By weighing.
By formula.
With special tables.

Each method determines the carat weight with a certain degree of accuracy.

Weighing

You can weigh a stone using special diamond-weighting scales. Weighing accuracy is up to thousandths.

The Formula

You can also use a formula, in which case it is necessary that the diamond is not set in the piece of jewelry. A special formula by Tavernier is used to find its weight:
m = (d^2) x h x 0.0061

where m is the weight of the stone, h is the height and d is the diameter. The accuracy of such calculations is up to 10% or more.

Size to Carat Table

Typically, we come across diamonds that are already encrusted in a piece of jewelry. It is not possible to take the stones out of their settings, so the carat weight is determined approximately. The high price of diamonds sometimes has nothing to do with the carat, it is due to their rarity and the play of colors that only natural stones have.

So, to determine how many carats are in a diamond, measure the diameter and then proceed according to the table below. This table establishes the relationship between the diameter and the weight of the stone.

Carat weight to size chart

Cut / Carat weight	0.5 ct	1.00 ct	2.00 ct	3.00 ct
Round	5 mm	6.5 mm	8 mm	9.1 mm
Princess	4.5 mm	5.5 mm	7 mm	8 mm
Pear	6*4 mm	7.7*5.7 mm	9*7 mm	12*8 mm
Marquise	8*4 mm	10*5 mm	13*6.5 mm	15*7 mm
Oval	6*4 mm	7.7*5.7 mm	9*7 mm	12*8 mm
Emerald	6*4 mm	7*5 mm	8.5*6.5 mm	10*7.5 mm
Heart	7*5 mm	7*5 mm	8.5*6.5 mm	10*7.5 mm
Asscher	4.5 mm	5.5 mm	7 mm	8 mm
Radian	6*4 mm	7*5 mm	8*6 mm	9.5*7.5 mm

As the weight of a stone changes, its price changes exponentially. A two-carat diamond is worth four times as much as a one-carat stone of exactly the same quality. Large diamonds have no fixed price on the market. Their value depends on the cut, clarity and color.

More information about diamonds

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