These days, you see a lot of ring shoppers place near-exclusive focus on the carat weight of the stones which they consider buying. To say this aspect is important, would be an understatement; of the 4 C’s, many experts find the carat weight to be the heaviest deciding factor when it comes to a stone’s value on the market. If you have skipped over this part of your diamond education, or simply wish to brush up, below is a detailed look on diamond carat weight, which should be some help when buying, say, a 1carat engagement ring.
What Exactly is Carat Weight?
Carat weight, along with three other major specifications, constitutes the 4 C’s of a diamond. These are part of the standard established by GIA to reliably gauge the attributes of any given diamond. One carat is the equivalent of 0.2 grams. The word “carat” is derived from “carob”, whose pods have peas that are extremely uniform in size. This is different from “karat”, which is a measure of fineness used for valuing gold.
How is it Measured?
The weighing of diamonds is typically done using a microbalance scale, with GIA doing it up to five decimal places to make sure things are kept highly precise. Normally though, you only have measurements going up to two decimal places in terms of accuracy. When buying a stone, it is always best to make sure you get the accuracy of weigh measurement up to the maximum number of decimal points.
Carat Weight vs. Diamond Size
It may make sense initially to equate the two with one another, but when you consider that some diamond shapes are simply bigger than others, this approach falls flat pretty quickly. Ruby, for example, is denser than diamond, which means a stone of the same size would figure higher in terms of carat weight. Take another example, where you have a brilliant diamond with a poor cut and consequently a thicker girdle than is normal for its size. Its weight would not register simply from looking at it.
Carat Weight and Price
Larger and heavier diamonds also happen to be rarer. This explains why you see so much coverage whenever a stone heavier than 100 carats gets mined. Larger diamonds come with a premium; the difference in price is usually seen to be exponential rather than geometrical. That means a 1.00 carat diamond would cost a lot more than double the price of a 0.50 carat diamond.
Prices Jump at Specific Carat Weights
You would find it almost impossible to tell which is which when holding a 1.01 ct diamond and a 0.99 ct diamond. Most people skip this and go for whole numbers, or symbolic ones like 0.75 ct, 0.50 ct, 0.25 ct, etc. They call these the “magic sizes”, because those right above them cost a little more per carat. Meanwhile, those right below cost less on the carat, making them the smart choice for budget-wary shoppers.
Carat Weight is Not the Same as Total Carat Weight
When you move away from one carat ring designs, you begin to see that many rings feature more than one precious stone. These rings each have a measure called “total carat weight” or “TCW”, which describes how much the diamonds weigh collectively. For instance, if you have an engagement ring with a 1.20 carat center stone and one 0.30 carat side stone each on the right and left of this, then the total carat weight of the ring comes up to 1.80 carats. This measure affects the price of any ring for sure, but not as heavily as the carat weight of the center stone.
When Does Per Carat Price Apply during Comparison?
When you buy a loose diamond, you would normally compare it with something similar. If, for instance, a 1.50 carat stone is tagged at $15,000, then you would do the math and figure out that its per-carat price is $10,000, and see if the other stone have a higher or lower value there. When doing this though, you need to be sure that the same laboratory graded both stones. GIA is good with things like this in terms of accuracy and consistency, but EGL really falls short a lot of the times. Moreover, the stones that you compared in this way should have similar cut, clarity, and color. The more variation there is along any of those factors, the less relevant your comparison would be.
Bigger is Not Always Better
With a significant budget, you would be able to get an engagement diamond with exceptional scores when it came to the 4 C’s. A lot of people see this as an opportunity to drive up the size aspect when choosing among the stones they have before them, but that does not always guarantee beauty, and it almost never brings good value for your money.