The GIA Diamond clarity-scale refers to how clean, or free of imperfections a Diamond is. The GIA standard for the clarity scale consists of:

FL, IF, VVS1, VVS2, VS1, VS2, SI1, SI2, ???, I1, I2, I3

So what is the SI3?

The SI3 was born out of the desire of the Diamond Industry to incorporate an extra grade to identify Diamonds in the lower range of the clarity scale. Many complained that there is too wide a gap between the SI2 and the I1 grade. Why not offer an SI3 grade to bridge the gap?

After EGL - Los Angeles (European Gemological Laboratory) started to issue the SI3 grade, even the Rapaport Diamond Report, or the Rap Sheet as it's known in the trade, added SI3 to its price list. For those who are unfamiliar with the Rap sheet, it is the definitive (but no longer only) price guide for Diamonds. It is used widely by the wholesale as well as retail industry.

Some say the SI3 is a good idea, others say it is a bad idea. We feel that it can be a good idea if implemented properly.

The problem with the SI3 today is that GIA, the largest and most widely accepted Gem Laboratory in the world, does not recognize SI3 grades. Bill Boyajian, President of GIA, wrote the following letter to Jewelers’ Circular Keystone JCK Magazine in May 2002:

“We have studied the SI3 suggestion at various times over the years, and yet again recently when proposed and adopted in principle by the World Federation of Diamond Bourses. However, GIA still concludes there is no reason to change our long-standing and universally accepted diamond grading system.”

The 4Cs of Diamonds (plus one)

Carat
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 are equal, the more a stone weighs, the more valuable it will be. Gemological laboratories measure carat weight when the diamond is loose (unmounted). While it is possible to estimate the weight of a mounted diamond, the lab uses ultrasensitive scales to achieve an exact weight, measured 3 decimal places, although the third decimal place is not usually mentioned at the retail level.

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)

Prices of diamonds are expressed in the trade as a price per carat. When we say that the Carat Weight has the biggest impact on the price of a diamond, not only is that true for the overall price of the stone, it is also true for the unit price per carat. That's why a 2 carat diamond is more than double the price of a 1 carat diamond.

Example:

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

It is important to understand that when you compare two diamonds of the same shape, the one having a larger carat weight does not always translate to the larger looking stone. Dimensions play an important role in the diamond's appearance.

Large tables may reduce the brilliance of a Round Brilliant Cut, however they also do make a diamond appear larger than it is. Some people are more concerned with the "loss of beauty" while others are happy that their diamond seems "bigger".

Another aspect in how a diamond is cut can affect the size appearance. If the Diamond's "girdle" is too wide, this can make a stone with a higher carat weight look smaller with no benefit to its appearance. That is because the diameter of the diamond is widest at the girdle and "hiding" weight there does not significantly alter the behavior of the light entering the diamond.

Keep in mind that finger size is an important consideration as well. Small fingers will make a diamond appear larger.

It is very common for people to disregard the other C's in favour 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 great.

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. What's most important if you are buying a Diamond for someone else, is that you know what their preference is.

How "big" is a carat?
Here's a simple trick to "understand" the meaning of a carat in realistic terms. Simply take a ruler and look at the table below. These are some approximate, sample carat-weight to diameter-widths for popular sizes.
0.25ct. ~ 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?
The effect of all the different properties of diamond on cost is discussed in more detail in the cost section. For carat weight, let's take a typical Diamond through different carat weights to see by how much it increases in price.

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 (as of the date this was written). 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.

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?

When discussing the topic of color in diamonds, you need to differentiate between mostly "colorless" diamonds and "fancy color" diamonds.

Grading "colorless" diamonds involves deciding how closely a stone's bodycolor approaches colorlessness. Most diamonds have at least a trace of yellow or brown bodycolor. The reason colorlessness is most highly valued is that diamonds in these ranges act like prisms, separating white light passing through it into a wide spectrum of colors. The more transparent the diamond, the wider the spectrum of colors. Chemical "impurities" in the diamond will filter out some of the colors which in turn reduces the "fire" effect when light bounces back out of the diamond and into your eyes. Other than "fancy colors". colorless diamonds tend to be more valuable. Rare colors such as blue, pink, purple, or red tend to be very expensive...and very beautiful.

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!

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

While it would be nice if technology brought about the ability to take the guesswork out of grading diamonds, we are not there yet. In terms of color, Sarin, one of the technology leaders in gemological equipment, has come out with a device called the "colorimeter".
The concept of the colorimeter is to be able to reliably judge a color impartially. Over the years, the device has improved considerably, however it is not as reliable as the eye yet and sometimes comes out with unexpected results. The one good thing is that the results tend to be repeatable. The labs use them from time to time, but do not rely on them at all. Maybe one day color grading will be done by a machine, the same way measurements are.
How much does "color" affect cost?
Let's take a typical diamond through different color grades and see how it can affect cost. 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
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.

Here is a table summarizing clarity grades:

Clarity FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3
Scale Flawless-
Internally Flawless Very Very Slightly Imperfect Very Slightly Imperfect Slightly Imperfect Imperfect
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.

If you really want to *see* what the differences in the Clarity Grades look like under magnification, there is an excellent book by Gary Roskin called Photo Masters for Diamond Grading. It provides photographs and explanations of different Clarity Grades and the inclusions causing them. We also have a Gem Gallery with many great pictures of inclusions and clarity grades.
How much does "clarity" affect cost?
Let's take a typical Diamond through different clarity grades to see how clarity affects prices. 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
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 consider 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 diamond, 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.

The goal in terms of extracting the greatest beauty from a Diamond, is to have light enter a Diamond, disperse the light as it bounces inside, thereby producing the different colors and sparkly effect, finally returning as much light to the eye as possible.

According to conventional wisdom, the proportions shown at the top of this page are the best for maximum light return. The 2-dimensional illustration below shows the theoretical path a ray of light will take through an ideal-cut Diamond. wellcut.gif (1520 bytes). As you can see, the rays of light entering the Diamond, reflect back to the eye. But it is 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...shallow1.gif (1325 bytes) or leak out of the bottom of the stone, like here...shallow2.gif (1239 bytes) Another side-effect of cutting this way is that it makes the stone appear larger. However, 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) deep1.gif (1275 bytes) and 2) deep2.gif (1385 bytes).

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.

One final note about cut. In the years since we've put up these tutorials, much has changed in how cut is perceived and marketed. A serious push was made to introduce systems of cut evaluation. There are many proponents of these new systems, however the technology behind it is not very impressive nor scientific. Computer simulations that do not take into consideration many of the variables that affect light return are being used as the basis of new cut grades by the gem labs. They do not compare to having an expert looking at a cut and judging it with the naked eye. And more importantly, cut is more subjective than the other "c"'s. While there is a clear reason to prefer the rarer 2 carat diamond to a 1 carat diamond, or a clear preference for a D color over a G color, some people prefer diamonds to be cut different ways. Some like bigger tables. Some find different proportions more pleasing. Some prefer fire over brilliance and vice versa.

According to GIA:

A polished diamond’s beauty lies in its complex relationship with light: how light strikes the surface, how much enters the diamond, and how, and in what form light returns to your eye.

The result is a display of three attributes. Brightness is the combination of all white light reflecting from the surface and interior of a diamond. Fire is the colored flashes that can be seen in a diamond. Scintillation describes the sparkle of light you see in a diamond, and the overall pattern of bright and dark areas when you look at a diamond face-up.

A polished diamond’s proportions affect its light performance, which in turn affects its beauty and overall appeal. Diamonds with good proportions optimize the interaction with light, and have good brilliance, fire, and scintillation.

The Design (weight ratio, durability) and Craftsmanship (polish, symmetry) of a diamond also affect its cut quality, and are considered in determining a diamond’s GIA Cut Grade.

Can you see from these sentences alone what the problems are? For example, brightness is white light. Which by definition takes away from Fire which results from Dispersion. How much Brightness is preferable to Fire? It's all so nebulous. The number of variables are too great to measure all this.

In the exuberance to bring a definitive cut grade to the end consumer, something has been lost along the way. Our advice to you is to ignore the official cut grades and judge the cut by how your eye finds it pleasing or not.

Cost
The most important "C" you have to think about is COST. You've probably heard the "salary guideline" of spending about two months salary on a diamond engagement ring. While it may be helpful to know what the industry is suggesting, that is probably not the best way to decide how much to spend on an engagement ring.

If you earn $30,000 a month, you can probably save 4 months salary easier than someone who is earning $1,000 a month can save 1 month's salary. And it's important to know what your fiance thinks of the matter. Every person has their own preference and communication in this matter is important.
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. In other words, the "per carat" price will be the same for a G/SI1 diamond of 0.52ct as it would be for a G/SI1 diamond of 0.63ct. If you know the per carat price, you simply multiply it by the carat weight. 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. If you have any questions on this matter regarding a particular stone, grab the measurements, fill out this form and ask away.
Pricing Terminology in the Diamond Business
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 carat Diamond 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 and 50 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:
Two diamonds!
Why? Because "carat", which is the Second C, is more valuable the bigger it is. One diamond of 1 carat is worth more than 2 Diamonds of 1 carat.