How To Determine The Size Of A Diamond

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How To Determine The Size Of A Diamond
How To Determine The Size Of A Diamond

Video: How To Determine The Size Of A Diamond

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The diamond is rightly considered the king of precious stones. In order to correctly assess the size of this royal stone, it is necessary to correlate its weight with the proportions and nature of the cut.

How to determine the size of a diamond
How to determine the size of a diamond


  • - carat scales;
  • - calculation table of diameters;
  • - vernier caliper;
  • - calculator.


Step 1

There are several ways to determine the weight of a diamond. The most accurate result can be obtained using special carat scales. One carat is equal to 0.2 grams. The scale of division of a carat consists of one hundred units, respectively, a gem is weighed to the nearest hundredths. At the same time, diamonds weighing less than 0.01 carats are considered crumbs. Depending on the mass received, stones are divided into small (less than 0.29 carats), medium (less than 0.99 carats) and large (more than 1 carat). Diamonds weighing more than 6 carats are sold, as a rule, through a special procedure - an auction.

Step 2

In cases where the stone cannot be weighed, for example, it is set into a piece of jewelry, its weight is calculated using a special formula - M = (D2) x H x 0, 0061. M is the mass of the sought after in carats, D is the diameter of the stone, H is its height. This formula is used in calculating the weight of standard round diamonds and has a margin of error within 10%. If the gemstone you are measuring has a distorted cut and asymmetrical edges, the formula error increases significantly. Another option for determining the mass of a diamond using the diameter is a special calculation table. To do this, measure the diameter of the diamond and correlate it with the data in the table. So a stone with a diameter of 2 mm. will weigh about 0.03 carats.

Step 3

When the mass of a diamond is known, attention should be paid to other essential characteristics that determine the size of the stone. These include proportions and cut quality. Since diamonds are cut by hand, stones can have the same weight but differ in size. Depending on the cut, the diamond may weigh more than what it looks like. Buying such a copy will be unprofitable, since the cost directly depends on the weight of the stone, and not on its size. In order not to overpay, measure the full height of the diamond with a caliper. Then calculate the ratio of this figure to the diameter of the stone as a percentage. For a standard round diamond, the height should not exceed 62 - 62.5% of the length of the diameter.

Step 4

Another subtlety in determining the size and value of a gemstone is the so-called transition masses. So, for example, a diamond weighing 1 carat (with a facet diameter of 6.5 mm) is visually identical to a stone of 0.95 carats (with a diameter of 6.3 mm), and their price will differ by more than one and a half times.

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