Diamond Grading 101
Not all diamonds are created equal. A diamond's value and quality is determined by looking at the 4 C's, Clarity, Cut, Color, and Carat Weight. This page is here to help you become an informed buyer, and understand these characteristics. A diamond's price will also be affected by it's shape, and whether or not it has been professionally graded.
Most diamonds contain imperfections or blemishes. These imperfections are called inclusions, or flaws. A diamond's clarity rating will be determined by the type, number, size, and location of the inclusions on the stone. Some inclusions are microscopic and require magnification tools and a trained eye to spot, some flaws may be visible to the naked eye.
As long as inclusions do not affect the passage of light through the diamond, they will not detract from the diamond's beauty.
Below is a chart showing the most common grading scale for diamond clarity. A Flawless stone is the highest and most expensive grade, and will be quite literally, flawless. An Imperfect stone, will have blemishes visible to the naked eye. Any stone from an SI to an IF rating, will have at least minor flaws, but none will be visible to the naked eye.
As long as inclusions do not affect the passage of light through the diamond, they will not detract from the diamond's beauty.
Below is a chart showing the most common grading scale for diamond clarity. A Flawless stone is the highest and most expensive grade, and will be quite literally, flawless. An Imperfect stone, will have blemishes visible to the naked eye. Any stone from an SI to an IF rating, will have at least minor flaws, but none will be visible to the naked eye.
| GIA Clarity Grades | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| FL. INT. FL. | VVS1 | VVS2 | VS1 | VS2 | SI1 | SI2 | I1 | I2 | I3 |
| Legend | |
|---|---|
| FL. | Flawless |
| INT. FL. | Internally Flawless |
| VVS | Very Very Slightly Included |
| VS | Very Slightly Included |
| SI | Slightly Included |
| I | Imperfect |
When a Diamond is cut to shape, the diamond cutter will try and shape the diamond to a certain set of proportions to achieve maximum brilliance. A diamond with maximum brilliance will allow the most possible light to pass through it, making it the brightest and most beautiful diamond possibe.
A diamond that has been cut to these proportions is considered to have an "Ideal Cut". Less than 1% of diamonds are cut to ideal specifications. The image above shows a round shaped diamond with an ideal cut.
At Bennett's, we evaluate the cut of every diamond we buy by using a precise millimeter gauge which evaluates width, depth, crown height, and pavilion depth.
A diamond that has been cut to these proportions is considered to have an "Ideal Cut". Less than 1% of diamonds are cut to ideal specifications. The image above shows a round shaped diamond with an ideal cut.
At Bennett's, we evaluate the cut of every diamond we buy by using a precise millimeter gauge which evaluates width, depth, crown height, and pavilion depth.
Diamonds are cut into a number of different shapes. No one shape is more beautiful than another, each cut is unique and a work of art. The choice of diamond shape will come down to personal preference.
Some of the most popular shapes are round, pear, oval, and emerald cut.
Some of the most popular shapes are round, pear, oval, and emerald cut.
Round Cut
Pear Cut
Oval Cut
Emerald Cut
The color of a diamond is determined by the hue of the stone. The highest quality stones will be colorless, or near colorless. Lower quality stones will have a yellow hue. This yellow hue can be faint, or fairly prominent.
The color grade will be a letter from D, to Z. The difference between two close grades, e.g. D and E, will be very subtle, so it may be better to look at the broader categories a diamond's caller may fall under.
A chart showing what category each letter grade is in, is shown below.
The color grade will be a letter from D, to Z. The difference between two close grades, e.g. D and E, will be very subtle, so it may be better to look at the broader categories a diamond's caller may fall under.
A chart showing what category each letter grade is in, is shown below.
| GIA Color Grades | Category |
|---|---|
| D | Colorless |
| E | |
| F | |
| G | Near Colorless |
| H | |
| I | |
| J | |
| K | Faint Yellow |
| L | |
| M | |
| N | |
| O | Very Light Yellow |
| P | |
| Q | |
| R | |
| S | |
| T | |
| O | Light Yellow |
| V | |
| W | |
| X | |
| Y | |
| Z |
Carat weight is the easiest of the 4 C's to determine. It is the weight of the diamond, measured in carats.(For the curious, 1 carat equals 200 milligrams.)
A Diamond's quality is subjective, some people may look at a diamond with an SI1 clarity, and say it is a VVS2 or a SI3 instead. At Bennett's we have a certified gemologist, with 35+ years of experience, that uses various pieces of equipment to guarantee the quality of all diamonds we list.
There are also professional diamond grading services offered by a few diamond labs. The biggest are the Gemological Institute of America(G.I.A), and the American Gem Society(A.G.S). Buying a professionally graded diamond, will come with a certificate of authentication, proving that your diamond has been graded using widely recognized standards. This will increase the price of any diamond you purchase.
If you want a certified diamond, just let us know and we will find you one. We also have a G.I.A. certified gemologist, that is able to grade, and issue G.I.A. certifications for any diamond we sell.
There are also professional diamond grading services offered by a few diamond labs. The biggest are the Gemological Institute of America(G.I.A), and the American Gem Society(A.G.S). Buying a professionally graded diamond, will come with a certificate of authentication, proving that your diamond has been graded using widely recognized standards. This will increase the price of any diamond you purchase.
If you want a certified diamond, just let us know and we will find you one. We also have a G.I.A. certified gemologist, that is able to grade, and issue G.I.A. certifications for any diamond we sell.