Carat Weight

The size of a diamond has the biggest impact on its price. The metric carat, which equals 0.20 gram, is the standard unit of weight for diamonds and most other gems. If other factors remain the same, the more a gemstone weighs, the more valuable it will be.

Here are several ways to express 1 carat:

• 1 ct.
• 200 milligrams
• 1/5 gram
• 100 points
• 4 grainer (not often used in retail environment)

It is very important not to mistake carat weight as referring to the dimensions of a diamond. It refers to weight only. Why the distinction? Because weight can hide in different parts of the stone. You can have well-cut, deep or shallow Diamonds. Some may appear larger than others due to their cut. This is very important and is explained in more detail in the Cut section.

Prices of diamonds are expressed in the trade as a price per carat. So when we say that the Carat Weight has the biggest impact on the price of the stone, we refer to the unit price per carat, not just the overall price of the whole stone. So when you are comparing prices, make sure you get this clear. To help you, here's an example:

Example 1:
Diamond "A" = 0.25 carats and costs $1,000 per carat. $1,000 x 0.25 = $250/stone.
Diamond "B" = 0.50 carats and costs $1,250 per carat. $1,250 x 0.50 = $625/stone.

It is very common for people to disregard the other C's in favor of getting the biggest possible stone they have budgeted for. Although SIZE DOES MATTER, we feel it is just as important for the quality of the stone to be high.

Some people may feel it is more impressive to wear a 2 carat diamond than a 1 carat diamond. But that's not necessarily true. A Ferrari may not be as big a car as an Oldsmobile, but most would consider it more impressive.

How "big" is a carat?

Well we've discussed carat weight, but you probably would like to know how big is a carat? To "understand" carat sizes in real terms look at the table below. These are some approximate, sample carat-weight to diameter-widths for popular sizes. Simply take a ruler and measure!

0.25 ct. - 4.1 mm	0.50 ct. - 5.2 mm
0.75 ct. - 5.9 mm	1.00 ct. - 6.5 mm

 

How much does "carat weight" affect cost?

How much the 5th C, which is Cost, is affected by each of the 4C's of Diamonds is discussed in more detail in the Cost section. For carat weight, let's take a typical Diamond for an example and see what happens when we take it through different carat weights.

A Diamond of G color and SI1 Clarity will be in one Category of prices when it is between 0.50 - 0.69 carats. When you take that same quality Diamond and increase the size to the next price category, which is the 0.70 - 0.89 carat range, the price increase will be approximately $1,100 per carat. Increase to the 0.90 - 0.99 carat range, and the price increase will be approximately another $800 per carat. Increase to 1.00 - 1.49 carat range, and the increase will be approximately another $800 per carat. If you increase to the 1.50 - 1.99 carat range, the price increase will be approximately $1,200 per carat.

Clarity

The clarity of a diamond refers to how clear, or "clean" the diamond is. The more "clean" the diamond, the higher the price. Most diamonds have "imperfections" in them. The clarity scale is a measure of the severity of those imperfections or "inclusions" as it is known in the trade.

For example, a deep break in a diamond which is not that visible when you look at the stone face-up, could sometimes have a greater impact on the clarity of a stone than a small black crystal which you can see very clearly face-up.

The following is the GIA Diamond clarity-scale:

FL-Flawless

These stones have no imperfections inside or on the outside of the stone under the magnification of a loupe of 10 power.

IF-Internally Flawless

These stones have no inclusions under a loupe with a 10 power magnification.

VVS¹,VVS²-Very Very Slightly Imperfect

These stones have very small inclusions which are very  difficult to see under a loupe with a 10 power magnification.

VS¹,VS²-Very Slightly Imperfect

These stones have small inclusions which are slightly difficult to difficult to see under a loupe with a 10 power magnification.

SI¹,SI²-Slightly Imperfect

These stones have inclusions which are fairly easy to see under a loupe with a 10 power magnification, or visible to the naked eye.

I¹,I²,I³-Imperfect

These stones have inclusions which range from eye visible to very easily seen to the naked eye.

SI³

Outside of the GIA Diamond clarity scale is a grade you may have seen called SI3. The Rap Sheet, which is a Trade Publication, honors the SI3 grade which is given out by EGL, the European Gemological Laboratory. It is described as a split between the SI2 and I1 clarity grade.

Search DiamondTalk for SI3.

How much does "clarity" affect cost?

The effect of all the different properties of Diamond on Cost is discussed in more detail in the Cost section. For clarity, let's take a typical Diamond for an example, and see what happens when we take it through different clarity grades.

Let's start with a 1.00 carat Diamond of G color and SI1 Clarity. If you move up to a VS1, you will pay approximately an extra $1000 per carat. Move up to VVS1, the increase will be approximately $700 per carat. Improve the clarity to IF and the increase will be approximately $700 per carat.

If you really want to *see* what the differences in the Clarity Grades look like under magnification, there is an excellent book by expert Gary Roskin called Photo Masters for Diamond Grading. It provides photographs and explanations of different Clarity Grades and the inclusions causing them.

Search DiamondTalk for messages by Gary Roskin

Color

The color of a diamond has the second biggest impact on its price, after carat weight. Did you know that diamonds come in every color of the rainbow?

Grading color in the normal range involves deciding how closely a stone's bodycolor approaches colorlessness. Most diamonds have at least a trace of yellow or brown bodycolor. With the exception of some natural fancycolors, such as blue, pink, purple, or red, the colorless grade is the most valuable.

If a diamond does not have enough color to be called fancy, then it is graded in a scale of colors ranging from Colorless to Light Yellow, "D" through "Z". A diamond with a "D" color is considered to be colorless. If the color is more intense than "Z", it is considered fancy. A fancy yellow diamond fetches a higher price than a light yellow diamond.

The Laboratories only grade diamonds which are unmounted or "loose", and they do so under special light. Once a loose diamond is mounted on a ring, even the trained professional cannot always tell the difference between, say a "D" color and an "E" or "F" color diamond!

How much does "color" affect cost?

The effect of all the different properties of Diamond on Cost is discussed in more detail in the Cost section. For color, let's take a typical Diamond for an example, and see what happens when we take it through different color grades.

Let's start with a 1.00 carat Diamond of K color and VS1 Clarity. If you move up to an H color, you will pay approximately an extra $1,700 per carat. Move up to F color, the increase will be approximately $1,100 per carat. Improve the color to D and the increase will be approximately $900 per carat.

Color

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Fancy

Scale

Colorless

Near Colorless

Faint Yellow

Very Light Yellow

<------Light Yellow------>

Color

Cost

The most important "C" you have to think about is COST. The few times you hear about cost, it is usually as a "salary guideline" or "buying tips" which may include "advice" to spend about two months salary on a diamond engagement ring. Would you like to know where the idea of two month's salary came from? A marketing person whose job it is to sell as many Diamonds as possible. The reality is that there's no "guideline". There are too many personal factors to consider.

You know your financial situation better than anyone. You have to decide on a budget for how much you want to spend and/or can afford to spend. Then go out and see what that budget can buy. To get an idea of prices, you can fill out our Multi-Jeweler Diamond-Search form, indicating the type of Diamond you are interested in. You can also go to our Diamond Suppliers section to find suppliers and last but not least, you can visit DiamondTalk for more information. Some of them list their prices right on their website. Make sure they have a certificate from a respectable lab, though!

How much does each "c" affect cost?

Let's take a typical Diamond, and change the various properties to see how it affects the price:

Carat:
A Diamond of G color and SI1 Clarity will be in one Category of prices when it is between 0.50 - 0.69 carats. When you take that same quality Diamond and increase the size to the next price category, which is the 0.70 - 0.89 carat range, the price increase will be approximately $1,100 per carat. Increase to the 0.90 - 0.99 carat range, and the price increase will be approximately another $800 per carat. Increase to 1.00 - 1.49 carat range, and the increase will be approximately another $800 per carat. Increase the carat weight to the 1.50 - 1.99 carat range, and the price increase will be approximately $1,200 per carat.

Color
Let's start with a 1.00 carat Diamond of K color and VS1 Clarity. If you move up to an H color, you will pay approximately an extra $1,700 per carat. Move up to F color, the increase will be approximately $1,100 per carat. Improve the color to D and the increase will be approximately $900 per carat.

Clarity
Let's start with a 1.00 carat Diamond of G color and SI1 Clarity. If you move up to a VS1, you will pay approximately an extra $1000 per carat. Move up to VVS1, the increase will be approximately $700 per carat. Improve the clarity to IF and the increase will be approximately $700 per carat.

Cut
Cut is a bit more complicated and depends on various factors, like the quality of Diamond you are considering. Ideal cuts are generally much more expensive than the others. But it needs to be judged on a case by case basis. To get more information, fill out this form: Diamond Question.

Pricing Terminology in the Diamond Business

We would like to clear up some confusion as to how pricing works in the Diamond industry. The price of Loose Diamonds in the wholesale market is stated in Dollars (Pesos, Dineros, Shekel, Italian Lira...) per Carat. This figure is multiplied by the number (or fraction) of carats being bought.

Example 1:
Jeweler buys 40 carats worth of Diamonds from Dealer at $2,000.00 per carat =
$2,000 X 40 carats = $80,000 (for 40 carats-worth of stones).

Example 2:
Consumer buys 0.50 carats worth of Diamonds from Jeweler at $3,000.00 per carat =
$3,000 X 0.50 carats = $1,500 (for 1 stone).

Sometimes Jewelers will quote to retail customers a per carat price or sometimes they will quote a price per stone. So a 0.50 ct. diamond can be quoted as $3,000.00 per carat, which comes to 0.50 x $3,000.00 = $1,500.00 for the diamond, or it can simply stated as $1,500.00 per stone. When buying a piece of Jewelry which may contain one or more type of gem, the price will always be per piece.

Total Weight

When you see T.W., or Total Weight, it will refer to the total carat weight, per gem type (at least they should and usually do break it down by gem-type). So a ring with emeralds and sapphires and diamonds could say:

Example 3:
Emerald t.w. = 0.25 cts., Sapphires t.w. = 0.31 cts., Diamonds t.w. = 0.75 cts.

This refers only to the weight as measured when the gems are loose and unmounted. It has nothing to do with the number of gems contained in the Jewelry. The above example could mean there were 5 emeralds, 7 sapphires, 100 diamonds as easily as it could mean that there were 2 emeralds, 2 sapphires and 2 diamonds.

QUICK CARAT COST QUESTION:

Which would be more valuable? 100 diamonds with a t.w. (total weight) of a carat? Or 2 diamonds with t.w. of a carat?
Answer: 2 diamonds! Why? Because Carat, which is the Second C, is more valuable the bigger it is. 1 Diamond of 1 carat is worth more than 2 Diamonds of 1 carat.

Cut

The cut of a Diamond is the only property which is totally dependent on man. Although often overlooked, cut is actually one of the most important aspects to look at when choosing your diamond. A Diamond cutter analyzes the rough diamond, and has to determine how to extract the most beauty and most profit out of the rough stone.

Cut refers to not only the shape of the diamonds, but its proportions and finish, factors which determine the sparkle of the diamond.

It is possible to take the same stone, and depending on which method the cutter decides to use, to either cut it into the most beautiful stone it can be despite heavy weight loss and perhaps lower monetary value. Or else, he can cut a stone to its maximum weight and monetary value, but lose some "brilliance" and "sparkle"!

You see, even if you have two equal polished diamonds, both the same carat size, both the same color, both the same clarity, they may look completely different. How? There are many different shapes, and facets in a diamond. The weight can be distributed in different parts of the stone. For example, here's a picture of an ideal-cut stone:

The affect of the "ideal-cut" is that when light enters the stone, the most light will reflect back out of the stone producing the "sparkle" and "fire" of the modern diamond, as illustrated here... . But its possible for a diamond cutter to extract more weight out of the diamond by increasing the diameter of the stone.

This will make the stone too shallow, and light may escape from the side of the stone, as shown here... or leak out of the bottom of the stone, like here... Another side-effect of this cut, is that it makes the stone appear larger. Don't be fooled by this. The fact that it appears larger than it is does not make it a better stone. If you compare a shallow stone to a well-cut stone, you will see the difference in how the well-cut stone "lights up".

By the same token, it is common to see the opposite problem. A stone which is cut too deep will "leak out light" in much the same way as the shallow stone. Here are two illustrations . . .
1) and 2) .

This is not to say that a shallow or deep stone is a sign of a poor, or "low-quality" diamond cutter. Sometimes the shape of the rough diamond makes it impractical to cut a stone closer to "ideal" proportions without losing significant weight. But it is important to note the "light leakage" which will result from this cut.

We have published a table comparing the GIA vs AGS Cut Grading Systems.

UPDATE: GIA has come out with some new research relating to the Ideal Cut. It is common knowledge that the classic model for cut which we have described above is lacking in many respects. One big problem with it is that this model is two dimensional, whereas Diamonds exist in three dimensions. For more information, see our Message Forums on this topic 1, 2.

How much does "cut" affect cost?

The effect of all the different properties of Diamond on Cost is discussed in more detail in the Cost section. For cut, it can vary depending on the quality of the Diamond.