Diamond Grading
Grading System of A DiamondDiamond Grading System
When purchasing certified diamonds it is important to understand the diamond grading System used by the laboratories performing the certification.
When buying a Diamond, you should always look for and review the Grading Certificate to ensure that it has been examined and graded by an independent professional grading lab.
NYG Diamond Grading Ceritificate covers numerous aspects of each individual diamond's qualities, including the 4Cs of diamond (Color, Cut, Clarity and Carat weight).
There are additional ratings, fluorescence, graining and measurements noted on a diamond certificate.
One of the main reasons to buy a Certified Diamond is that the Certificate uniquely identifies your diamond, and states all its features that set it apart from all other diamonds.
It enables you as a Customer to objectively compare diamonds, and get assurances about the quality of the diamond.
Clarity Scale System
Scale list of Diamond ClarityDiamond Clarity Scale according to NYG Lab
Grading
Details
0
1
2
3
4
5
6
7
8
9
10
Flawless/IF
Very Very Slightly Included
Very Slightly Included
Slightly Included
Included
FL/IF
VVS1
VVS2
VS1
VS2
SI1
SI2
I1
I2
I3
FL (Flawless) : No internal or external imperfections.
IF (Internally Flawless) : No internal imperfections. Extremely rare and valuable.
VVS1 - VVS2 (Very, Very Slightly Included) : Very difficult to see imperfections under 10x magnification. An excellent quality diamond.
VS1 - VS2 (Very Slightly Included) : Inclusions are observed with effort under 10x magnification, but can be characterized as minor. Less expensive than the VVS1 or VVS2 grades.
SI1 - SI2 (Slightly Included) : Imperfections are visible under 10x magnification, and may be visible with the unaided eye. A good diamond value.
SI3 - I1 (Included) : Inclusions that are almost always visible to the naked eye.
I2 - I3 (Included) : Inclusions are visible to the unaided eye. Not carried by Brilliant Earth.
Color Scale System
Scale list of Diamond ColorDiamond Color Scale according to NYG Lab
Grading
Details
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
To
Fancy Yellow
Colorless
Near Colorless
Faint
Very Light
Light
Fancy Yellow
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Fancy Yellow
D-E-F (Colorless) : The rarest and most valuable diamonds. There are differences in color between D, E, and F diamonds. They can be detected only by a gemologist in side by side comparisons, and rarely by the untrained eye.
G-H-I-J (Near Colorless) : More common than the higher grades. They tend to be a great value. An I-J diamond may retail for half the price of a D diamond. Within the G-H-I-J range, price tends to increase 10-20% between each diamond grade.
K-L-M (Faint Yellow) : Beginning with K diamonds, a yellow tint is more easily detected by the naked eye. K diamond is often half the price of a G diamond.
N-O-P-Q-R (Very Light Color) : Slight or obvious color. Diamonds in the N-O-P-Q-R color range have an easily seen yellow or brown tint. Much less expensive than higher grades.
S-T-U-V-W-X-Y-Z (Light Color) : For almost all customers, S-Z diamonds have too much color for a white diamond. Very much less expensive than higher grades. Cut Scale System
Scale list of Diamond CutDiamond Cut Scale according to NYG Lab
Grading
Details
0
1
2
3
4
5
6
7
8
9
10
Ideal
Excelelnt
Very Good
Good
Fair
Poor
Super Ideal Cut : Cut to the most exacting standards. On the diamond certificate, graded as "Excellent" or "Ideal" for cut, polish, and symmetry. These diamonds will also show a "hearts and arrows" facet pattern, have the most desirable girdle and culet dimensions. It proportioned to return the maximum possible light.
Ideal Cut : Represents roughly the top 3% of diamond quality based on cut. Exquisite quality cut to create the optimal combination of brilliance and fire. Reflects nearly all light that enters the diamond. A exquisite and rare cut.
Very Good Cut : Represents roughly the top 15% of diamond quality based on cut. Superior quality cut that reflects nearly as much light as the ideal cut, but for a lower price.
Good Cut : Represents roughly the top 25% of diamond quality based on cut. Premium quality cut to optimize the size without sacrificing quality or beauty. Reflects most light that enters.
Fair Cut : Represents roughly the top 35% of diamond quality based on cut. Adequate quality cut which reflects some light while maximizing weight. While not as brilliant as a good cut, still a quality diamond.
Poor Cut : Inadequate quality cut that reflects minimal amount of light. Brilliant Earth does not provide diamonds with cut grades of poor. 
