Carat weight is very easy for a consumer to understand and is familiar with the terminology but the consumers do often confuse weight with dimensional size. Also these same consumers, among others will not completely understand the prices differences based on carat weight. They think a 1ct diamond is twice the size of a ½ carat and they think it’s more expensive.
One point (abbreviated pt) equals 0.01ct or 1/100ct so 100pts add up to 1ct.
Carat weight fractions are approximate and they usually apply to the limited ranges of weight. This is done for simplicity but many retail locations are slowly stopping the use of fractions because the ranges can lead to misunderstandings. Now many diamond labels are being printed like 0.28 so it is less confusing for the consumer and salesperson.
Example: if a diamond is a 1/4ct the range would be 0.23-0.29
A diamonds carat weight is limited to the space to grow in, nutrients to grow in, and the temperature-pressure conditions. The argument is 1 out of 1,000 diamonds grow to a 1 carat or larger.
Weight and Diamonds:
Buying a diamond in an unmounted state is actually easier to see the diamond weight, the diamond color and the true beauty of the scintillation and dispersion. Many firms today do not sell diamonds unmounted because it makes it harder for a swap to happen where the thief would use a Moissanite stone during a “distraction theft”. Those firms that still sell unmounted have heavily secured show rooms with the proper tools they will need during a presentation to answer questions and can show only one or two diamonds at a time. When you visit these retailers make sure they weigh it before and after the sale. This is for your benefit only.
In the USA, a diamond weight is usually rounded to the nearest point. So a diamond weighing 0.995 is rounded to 1.0. This is compliant with the FTC Guidelines which states “a diamond must be accurate within a half point (0.005ct).
There are several reasons a diamond’s weight would be estimated:
- A diamond is already mounted and the appraiser estimates its weight by measuring key dimensions and using those in a special mathematical formula. This process is safer and cheaper than removing the diamond from the mounting, weighing it and then resetting it.
- The diamonds are purchased in large parcels which were sorted by diamond sieves. These interchangeable screens have different sized holes that correspond to different sized diamonds. The sorting starts out sifting out the smaller diamonds slowly moving up to the larger diamonds. This process stops when all the diamonds are sorted.
Because the consumer is used to buying meats, fruits and vegetables by weight, they will automatically think that a diamond with more weight in more expensive.
Value and Weight:
Because the consumer is used to buying meats, fruits and vegetables by weight, they will automatically think that a diamond with more weight in more expensive. This isn't the case. The price depends on rarity. A 1 ounce bar of gold is no rarer than two 1/2 ounce gold bars so the price will not be more. But a 1ct diamond is much rarer than two 1/2ct diamonds of similar quality. Because the 1ct is rarer, it will cost more than both 1/2cts.
Now here is the great part... if you take a 1ct diamond of lower quality and compare it to two 1/2cts of higher quality, the two 1/2ct diamonds will be more expensive than the lower quality 1ct. Why? Rarity. Color and clarity also play a part in rarity... which we will cover.
Per-Carat-Price:
Sometimes you will hear or read that diamonds or gems go for X amount per carat, you will need to understand how this plays out.
To find the true retail cost of a diamond, you would multiply per-carat-price by the weight (using fake numbers off the top of my head).
$1,500 per ct X 1.50ct = $2,250.00
(fifteen hundred per carat multiplied by one and one half carat weight equals two thousand two hundred fifty dollars and no cents.
FTC GUIDE - 23.17 "Misrepresentation of weight and 'total weight'":
1- It is unfair or deceptive to misrepresent the weight of a diamond
2- It is unfair or deceptive to use the word "point" or any abbreviation in any representation, advertising, marking, or labeling to describe the weight of a diamond, unless the weight is also stated as decimal parts of a carat (example - 25 points or .25 carat).side note to #2:A carat is a standard unit of weight for a diamond and is equivalent to 200 milligrams (1/5 gram). A point is a one one-hundredth (1/100) of a carat.
3- If a diamond weight is stated as a decimal parts of a carat (.47 carat), the stated figure should be accurate to the last decimal place. If a diamond weight is stated to only one decimal place (.5), the stated figure should be accurate to the second decimal place (.5 carat could represent a diamond weight between .495-.504).
4- If a diamond weight is stated as fractional parts of a carat, a conspicuous disclosure of the fact that the diamond weight is not exact should be made in close proximity to the fractional representation and a disclosure of a reasonable range of weight for each fraction (or the tolerance being used) should be made.side note to #4:
When fractional representations of diamond weight are made, as described in paragraph 4 of this section, in catalogs or other printed materials, the disclosure of the fact that the actual diamond weight is within a specified range should be made conspicuously on every page where the fractional representation is made. Such disclosure may refer to a chart or other detailed explanation of the actual ranges used. example - "Diamond weights are not exact; see page XXX for ranges".
Just in case you wanted to know:
- The Carob tree was abundant in gem trading regions of the ancient world and the tree’s, a peapod family member, are uniform in weight. Early merchants used these seeds as counterweights when weighing gems.
- The "unnamed brown" diamond weighs in at 545.67 carats is the biggest polished diamond.The "Great Star of Africa" or "Cullinan I" is the largest fine quality diamond weighing in at 530.20 carats.
- In 1942 the largest diamond was found in the United States weighing 40.23 carats and properly named the "Uncle Sam" diamond. The mine is located in Arkansas and named the Murfreeboro Mine. It was later cut into an Emerald Cut that weighs 12.23 carats. Other Diamonds found in the Murfreeboro Mine are; "Amarillo Starlight" weighing 16.37 carats and the "Star of Arkansas" weighing 15.33 carats.
- The Cullinan Diamond was found at the Cullinan mine, in 1905; the size of a man’s fist, it weighed 3 106 carats, making it the largest rough diamond ever found. It was cut into nine major stones - the largest being 530.20 carats - and 96 brilliants. Amazingly in 1986 this mine also presented the planet’s largest polished diamond, the 545.67 carat Golden Jubilee cut from a 755.50 carat rough diamond.