Perhaps you’ve heard that diamonds are commonly measured in terms of carats and points. Let’s see what these units of measurement mean and how you can calculate them.
What Are Diamond Carats and Points?
Carats and points are units of mass commonly used to measure the weight of diamonds and other gemstones.
One carat is equal to 200 milligrams, or 0.2 grams.
One point is equal to 1/100th of a carat. So, it follows that one point equals 2 milligrams, or 0.002 grams.
Measuring Diamond Carats and Points
To measure the carats and points of a diamond, you need to weigh the stone in grams or milligrams (or ounces), and then express its weight in terms of points and carats.
We suggest going through the following steps:
1. Weigh the diamond.
To weigh the diamond, it’s best if you use a sensitive scale that can measure milligrams.
The stone should be loose when you put it on the scale – i.e., if the diamond is mounted, you will need to first remove it from the setting.
2. Record the diamond’s weight in milligrams.
Look at the scale’s display. If the weight number is shown in grams, simply multiply it by 1,000, and write the result down.
3. Determine the carats of the diamond.
To calculate the diamond’s carats, divide the weight of the stone in milligrams by 200.
For example, if the scale shows 263 milligrams, this is equal to 1.315 carats (263/200).
3. Determine the points of the diamond.
After you’ve converted the stone’s weight into carats, look at the number after the decimal point. Dividing that number by 100 will give you the points of the diamond.
For example, if your stone weighs 1.315 carats, you can see that the number after the decimal point is 315, and dividing it by 100 yields 31.5 points.
4. Express the weight of the diamond in terms of carats and points.
After you’ve figured out how many carats and points are in your diamond, you can express its weight in these terms.
From our example above, the mass of a diamond that weighs 1.315 carats can be expressed as 1 carat and 31.5 points.
Converting Diamond Carats and Points to Grams and Milligrams
Now that you know how to calculate the weight of a diamond in carats and points, it is worth taking a quick look at how this conversion works the other way around.
To calculate the weight of a diamond in milligrams from carats and points, start by dividing the points number by 100 and adding it to the carat number.
For example, if a diamond weighs 1 carat and 62 points, divide 62 by 100, and add 0.62 to 1 – the result is 1.62 carats.
Next, multiply the carats of the diamond by 200 to obtain its weight in milligrams.
In the above example, this results in 324 milligrams for the stone’s weight (1.62 carats x 200), or 0.324 grams.