Grading System

 Diamond is Beautiful Diamonds are the most sought-after gems on earth. Each one is unique. And each has specific qualities that establish its value.


About Parishi Diamond Grading
  • We educate our customers about our minute grading system on various factors.
  • We manufacture 0.30 cts to 10 cts sizes in Round, Princess, Marquise, Pear, Oval, Square Emerald, Emerald, Square Radiant, Radiant, Heart, Cushion etc.

shape

Carat
  • The Carat is the measure of the actual weight of the diamond. A carat is divided into 100 points. A 0.50 carat diamond may also be referred to as 50 points.
  • Stones that have too high a depth percentage carry more weight in the height of the diamond where it does not add to the visual size appearance.
Price consideration with Size Range. Weight (unit): 1ct=100 cents 5cts = 1.000gms
0.15 0.15 - 0.17
0.18 0.18 - 0.22
0.23 0.23 - 0.29
0.3 0.30 - 0.39
0.4 0.40 - 0.44
0.46 0.45 - 0.49
0.5 0.50 - 0.59
0.6 0.60 - 0.69
0.7 0.70 - 0.74
0.75 0.75 - 0.79
0.8 0.80 - 0.89
0.9 0.90 - 0.99
1 1.00 - 1.19
1.2 1.20 – 1.49
1.5 1.50 – 1.69
1.7 1.70 – 1.99
2 2.00 – 2.99
3 3.00 – 3.99
4 4.00 – 4.99
5 5.00 AND ABOVE
 

Color
D-
Colorless nearly to D color
D
Absolutely colorless. The highest color grade, which is extremely rare.
E+

Colorless nearly to D color
E
Colorless. Only minute traces of color can be detected by an expert gemologist. A rare diamond.
E-
Colorless nearly to E color
F+

Colorless nearly to E color
F
Colorless, Slight color detected by an expert gemologist, but still considered a 'colorless' grade. A high-quality diamond. 
F-
Colorless nearly to F color
G+
Colorless nearly to F color
G
Near-colorless. Color noticeable when compared to diamonds of better grades, but these grades offer excellent value. 
G-
Near colorless close to G color
H+

Near colorless close to G color
H
Near-colorless. Slightly off-white when compared to diamonds of better grades but these grades offer excellent value.
H-
Near colorless close to H color 
I+
Near colorless close to H color 
I
Off-white when compared to diamonds of better grades. Color slightly detectable. A very good value stone.
I-
Off-white diamond but close to I color.
J+
Off-white diamond but close to I color.
J
Light color detectable with 10x diamond loupe. A very good value stone.
J-
This diamond is very close to J color diamond but not exactly J color 
K+
This diamond is very close to J color diamond but not exactly J color 
K
Light color detectable by the naked eye. A very good value stone.
K-
This diamond is very close to K color diamond but not exactly K color
L+
This diamond is very close to K color diamond but not exactly K color
L
Noticeable color. The color is detectable by the naked eye. A very good value.
L-
This diamond is very close to L color diamond but not exactly L color diamond 
M+
This diamond is very close to L color diamond but not exactly L color diamond 
M
Clearly visible color. Detectable with naked eyes. A very good value. 
M-
Clearly visible color. Detectable with naked eyes. A good value. 
N+
Clearly visible color. Detectable with naked eyes. A good value. 
N
This diamond is very close to N+ color diamond but not exactly N+ color diamond
N-
Clearly visible color. Detectable with naked eyes.
O+
Clearly visible color. Detectable with naked eyes.
O
This diamond is very close to O+ color diamond but not exactly O+ color diamond 

 

Clarity
 
  • L Flawless
Diamonds in this range have no inclusions, neither internal nor external.
  • IF Internally Flawless
No internal inclusions visible with 10x magnification. There may be some tiny external irregularities in the finish.
  • VVS1 Very very slightly included 1
Extremely difficult to see the inclusion. Even difficult to spot by trained eyes with 10 x.
  • VVS2 Very very slightly included 2
Still difficult to see the inclusions with 10x magnification but easier than VVS1.
  • VS1+ Better than VS1
Slightly better than VS1.
  • VS1 Very slightly included 1
Little difficult to see the inclusions with 10x magnification.
  • VS2+ better than VS2
Slightly better than VS2
  • VS2 Very slightly included 2
Very small inclusions visible with 10x magnification
  • SI1+ better than SI1
Slightly better than SI1.
  • SI1 Slightly included 1
Small inclusion visible with 10x magnification.
  • SI1- lower than SI1
Slightly lower than SI1
  • SI2+ better than SI2
Slightly better than SI2
  • SI2 Slightly included 2
Small inclusions easily visible with 10x magnification.
  • SI2- lower than SI2
Slightly lower than SI2.
  • SI3+ better than SI3
Slightly better than SI3.
  • SI3 Slightly included 3
Inclusions that may be visible to the naked eye for a trained observer.
  • SI3- Slightly lower than SI3
Slightly lower than SI3.
  • I1+ better than I1
Slightly better than I1
  • I1 Included 1
Inclusions that may be easily visible to the naked eye for a trained observer.
  • I1- lower than I1
Slightly lower than I1
  • I2+ better than I2
Slightly better than I2.
  • I2 Included 2
Many flaws clearly visible to the naked eye that also decrease the brilliance.
  • I2- lower than I2
Slightly lower than I2.
  • I3+ better than I3
Slightly better than I3.
  • I3- lower than I3
Slightly lower than I3.
  • I3 Included 3
Many flaws clearly visible to the naked eye which decrease the brilliance and compromise the structure of the diamond, making it more easily cracked or chipped.td>
 

Cut / Polish / Symmetry

The cut is the most important element to reflect brilliance and is determinable by 3 separate descriptions:

  • The cut is the most important element to control brilliance, scintillation and fire.
  • The sparkling quality of the cut is to be determined by 3 separate factors:

1. Proportions

2. Polish

3. Symmetry

 

How Diamond Laboratories grade Cut: Proportions - Polish - Symmetry

1. Proportions

Too shallow and / or too deep cut diamonds will loose brilliance through the side and bottom.

The result is a dull diamond with less brilliance, affecting the ultimate value in terms of quality and price!

Cut grading : Excellent, Very Good, Good, Fair, Poor or Unusual.

2. Polish

Finish grade or polish for ideal cut diamonds are described as following:

All facets of a diamond are carefully polished to eliminate all imperfections, characteristics such as abrasions,

scratches, nicks and polishing marks on the surface of the diamond to give the mirror shine and the final beauty touch.

Polish grading: Excellent, Very Good, Good, Fair, Poor or Unusual

3. Symmetry

is the balance and regularity / evenness of facets.

Facets are compared in opposing pairs, defined  as following:

Symmetry grading: Excellent, Very Good, Good, Fair, Poor or Unusual

 

Triple Excellent cut

When proportions, Polish and Symmetry are graded Excellent it is named Triple Excellent

 

Ideal cut = Perfect cut = Triple Excellent + Hearts & Arrows = Best Value!

When Proportions, Polish, Symmetry are graded Excellent

4. Hearts and Arrows - The Top in the Art of cutting read all about.


Fluorescence

Diamond Fluorescence

  • Fluorescence, the effect ultraviolet (UV) light has on a diamond, is an important consideration when selecting a diamond. When UV light strikes a diamond with fluorescent properties, the stone emits a glow that is usually blue, but can also reflect shades of green, yellow, white, pink, orange, and red. The sources of fluorescence, boron and nitrogen, are the same mineral properties that lend color to a diamond.

Fluorescence can occur in different intensities. Gemological laboratories rate the fluorescence of each diamond on a scale from "None" to "Very Strong".

 

None, Nil, Negligible

No fluorescence, no influence on color

Faint, Slight

Weak fluorescence, not a significant influence on color (barely perceptible)

Medium

Average fluorescence, small influence

Strong, Extremely Strong

Strong influence, substantial color influence

The Fluorescence Effect

Fluorescence can enhance or detract from the beauty of a diamond. The bluish tint can improve a lower-color diamond (J-M color rated) by cancelling out the faint yellow, resulting in a colorless appearance. However, in a very high-color diamond (D-F color rated), fluorescence may have the opposite effect.


Types of Fluorescence
GRADE
BL
YL
WH
OR
GR
DESCRIPTION
Blue Fluorescence
Yellow Fluorescence
White Fluorescence
Orange Fluorescence
Green Fluorescence

Types of Inclusion
Table Inclusion
GRADE
T0
T1
T2
T3
T4
DESCRIPTION
Almost Table Clean
Minor Inlcusion In Table
Medium Inclusion In Table
Major Inclusion In Table
Most Inclusion In Table
Black Inclusion
GRADE
B0
B1
B2
B3
B4
DESCRIPTION
Almost No Black Inclusion
Minor Black Inclusion
Medium Black Inclusion
Major Black Inclusion
Most Black Inclusion
Inclusion Pattern
GRADE
S1
S2
C1
C2
C3
DESCRIPTION
Scattered Inclusion
Semi Scattered Inclusion
Light Concentrated Inclusion
Semi Concentrated Inclusion
Concentrated Inclusion
 
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