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DIAMOND DEFINITIONS AND REFERENCE TABLES
Clarity: In gemstones, the incidence of inclusions and surface blemishes. One of the “four C’s” in Diamond grading. There are
several clarity grading scales throughout the world. The clarity grading scale used in this report is that of the G.I.A. Some of the
grades are split (e.g. VVS1 and VVS2). Size, position and number of inclusions determine the distinction between the split
grades. The descriptions below assume an expert eye using a 10X loupe corrected for spherical aberration. The following
diagram is not literal and is for illustration purposes only.
FL: Totally free of any internal or external blemishes.
IF: Free of any internal blemishes.
VVS: Extremely small internal blemishes that are difficult, to extremely hard to find.
VS: Very small internal blemishes that are: not too difficult to, easy to detect.
SI: Small internal inclusions which are very easy to find.
I1-I2: Internal characteristics that are visible to the trained, but unaided eye. They may diminish the brilliance.
I3: Large and/or numerous internal blemishes that are easily visible to the naked eye. Brilliance is diminished,
and structural integrity may be jeopardized.
Color: The classification of body color of cut diamonds. One of the “four C’s” in diamond grading. There are several color grading
scales used throughout the world, the scale used in this report is that of the GIA. The range is from colorless (“D”) to yellow,
brown or grey (“Z”), beyond is termed Fancy.
The following diagram is not literal and is for illustration purposes only.
Cut: The following is a modified table of diamond proportion classifications published by David Atlas and Joseph Tenhagen,
copyrighted in 1997.
DIAMOND PROPORTION GRADING SCALES - RANGE OF PARAMETERS
CLASS CLASS I
Ideal/Premier
AiIdl
CLASS II
Fine
I’lFi
CLASS III
Commercial
Cil
CLASS IV
Promotional
SHAPE
Round Round Pear, heart,
oval, marquise
Emerald,
radiant,
princess
Round Pear, heart,
oval, marquise
Emerald (E)
radiant,
princess
Round Pear, heart,
oval,
marquise
Emerald,
radiant,
princess
Table %
53-60 > 1/2 ct
53-62 < 1/2 ct
58-61.9
62-64
56-60
63-64
59-61
65-69
52.9-57.9
64.1-70
52-55.9,
64.1-70
53-58.9
68.1-76
<49-50.9,
70.1->72
<50.0-51.9
70.1->72
<50-52.9
76->78
Depth %
58.3-62.9 58-59
61-62
58-59
63-65.4
58-60
65-69
56.5-57.9,
62.1-65
46-57.9,
65.5-71
56-57.9
69.1-78
<56-56.4,
65.1->67
<43-45.9
71.1->73
<53-55.9
78.1->80
Crown Angle
degrees
34-35 31.6-32
32.1-36.4
31.6-33
34.4-36
31.6-32
34.4-36
29.6-31.5,
36.5-39.4
30-31.5,
36.1-37.5
29.6-31.5
36.1-37.5
<29-29.9,
37.8->39
<29-29.9
37.6->38
<29.0-29.5
37.6->38
Crown Height
%
16.2 11.1-15.5
11.1-12
13.7-15.6
11.1-11.5
12.9-15.6
15.6-20.1
8.5-11
8.7-11
15.7-18.4
9.5-11.0
15.6-16,17.4-
18.4
20.2 >21.8
<7.7-8.4
<7.8-8.6
18.5>19.5
<7.8-8.7
18.5->19.5
Girdle Size
slightly thick -
medium
thick - thin thick - thin thick - thin very thick -
very thin
very thick -
very thin
very thick -
very thin
ex thick -
ex thin
ex thick –
ex thin
ex thick –
ex thin
Pavilion Depth
%
42.5-43.5 42-42.4
42.5-44
42.0-42.5
44-46
40-41.9
44.1-46
40-42
46.1-48
<38-39.9
46.1->48
<39-39.9
48.1->50
Finish: polish
and Symmetry
very good-
excellent
good-
excellent
very good-
excellent
good-excellent good-fair good-fair good-fair fair-poor fair-poor fair-poor
L/W Ratio
P=pear, O=oval,
H=heart,
E-Emerald
M=marquise
R-Radiant Pr-
Princess
P 1.50-1.75
M 1.75-2.25
H 0.98-1.02
O 1.33-1.66
E .95-1.75
R .95-1.75
Pr .95-1.75
P 1.26-1.99
M 1.51-2.49
H 1.24-0.91
O 1.26-1.74
E 1.51-2.49
R 1.24-0.91
Pr 1.26-1.74
< Class 3
min.-
> Class 3
max.
< 0.91-1.51
(Class 3
minimum)