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Grading Lab Survey
Introduction
Method of Survey
Results
- Clarity and Color
- Cut Grades
- Clarity Plots
- Laser Inscription
- Girdle Thickness
- Measurements
- Pricing
 - Price Differences
Discussion
- Brand Value
- Appraisal
Conclusion
Acknowledgements
Appendix I
Appendix II
Appendix III
Appendix IV
Appendix V

Diamond Tutorial
 
   
 
Appendix III. Proportions and Measurements
 

No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Total Depth %
GIA 63 59.8 60.6 62.2 61.9 61.9 61.5 61.5 60.9 61.8 63.0 62.8 61.5 60.4 61.2 56.9 63.0
AGS 63.2 60.1 60.8 62.6 61.8 61.8 61.4 61.2 60.8   63.0 63.4 61.6 60.8 61.4 57.3 63.4
EGL 63.1 60.4 60.7 62.4 62.3 62.1 61.8 61.9 61.1 62 63.3 63.3 61.8 60.8 61.5 57.4 63.5

Table %
GIA 55 60 61 59 53 54 56 57 57 56/57 59 58 60 56 54 62 54
AGS 54 59 60 59 54 55 57 57 57   59 58 60 55 54 61 54
EGL 54 58 60 58 54 54 56 57 57 56 59 58 60 56 53 62 54

Girdle
GIA Med

S.Thk
F
Med


F
Thn

Med
F
Thn

Med
F
Med


F
Thn

Med
F
Med


F
Thn

Med
F
Thn


F
Med

S.Thk
F
S.Thk


F
Thn
-
Thk
F
Med
-
S.Thk
Thn Med Thn
-
Med
F
Med
-
Thk
F
AGS Med

Thk
F
Thn

S.Thk
F
Thn

S.Thk
F
V.Thn

Med
F
0.9%
-
2.0%
F
0.7%
-
1.5%
F
1.5%
-
2.2%
0.7%
-
1.5%
F
0.7%
-
1.2%
F
  S.Thk


F
Thn
-
Thk
F
Med
-
Thk
Thn Thn
-
Med
Thn
-
Med
F
S.Thk
-
Thk, F
EGL Med

S.Thk
F
Med


F
V.Thn

Thn
V.Thn

Thn
Thn


F
Thn


F
Thn

med
F
0.7%
-
1.3%
Thn


F
Thn
-
Med
F
S.Thk


F
X.Thn
-
S.Thk
F
Med
-
S.Thk
SF
Thn Med
-
S.Thk
Thn
-
Med
F
S.Thk
-
Thk
F

Diameter Min (mm)
GIA 5.72 6.00 6.63 6.58 5.49 5.43 5.44 5.48 5.78 5.67 5.86 5.63 5.79 6.79 6.50 7.15 5.62
AGS 5.71 5.99 6.64 6.59 5.50 5.43 5.45 5.5 5.79   5.87 5.62 5.79 6.79 6.50 7.14 5.62
EGL 5.71 5.99 6.63 6.58 5.47 5.41 5.43 5.47 5.76 5.65 5.85 5.60 5.77 6.77 6.49 7.13 5.61

Diameter Max (mm)
GIA 5.81 6.05 6.68 6.63 5.52 5.46 5.48 5.51 5.81 5.69 5.92 5.70 5.85 6.82 6.60 7.19 5.65
AGS 5.81 6.05 6.7 6.63 5.54 5.47 5.49 5.52 5.82   5.92 5.69 5.87 6.80 6.59 7.18 5.65
EGL 5.78 6.03 6.68 6.62 5.51 5.45 5.46 5.51 5.8 5.67 5.91 5.67 5.88 6.81 6.59 7.16 5.66

Total Depth (mm)
GIA 3.63 3.6 4.03 4.11 3.41 3.37 3.36 3.38 3.53 3.51 3.71 3.56 3.58 4.11 4.01 4.08 3.55
AGS 3.61 3.62 4.05 4.14 3.41 3.37 3.36 3.37 3.53 3.71 3.58 3.59 4.13 4.02 4.10 3.57
EGL 3.63 3.63 4.04 4.12 3.42 3.37 3.37 3.39 3.54 3.51 3.72 3.57 3.59 4.12 4.02 4.10 3.57

Pavilion Angle
AGS 40.8 41.4 41.3 41.1 40.9 40.8 41.1 41 41.8 41.2 41.5 40.9 41.1 41.1 40.9
EGL               41.2                  

Pavilion Depth %
AGS 42.9 43.7 44.3 43.6 43.3 43.1 43.0 43.4 43.2   44.3 43.4 43.9 43.2 43.4 43.4 43.2
EGL 42.8 44.3 44.3 43.5 43.5 43.3 43.1 43.8 43.5 42.8 44.6 43.4 44.1 43.2 43.6 43.7 43.2

Crown Angle
AGS 35.4 32.3 33.2 34.5 34.0 34.4 34.3 34.2 34.1   35.9 37.2 34.3 34.9 33.7 29.7 34.7
EGL               34.4                  

Crown Height %
AGS 16.3 13   14.2 15.6 15.4 14.8 14.5 14.5   14.8 15.8 13.7 15.5 15.3 11.0 15.8
EGL 16.5 13.1 13.2 14.5 15.7 15.7 14.9 14.8 14.7 14.8 14.8 16.0 13.9 15.5 15.4 10.9 16.0

Culet
GIA N N N N N N N N N N N N N N N N N
AGS P P P P P P P P P   P P P P P P P
EGL N N N N N N N N N N N N N N N N N


Abbreviations
Girdle
X.Thn - Extremely Thin
V.Thn - Very Thin
Thn - Thin
Med - Medium
S.Thk - Slightly Thick
Thk - Thick
F - Faceted
Culet
N - None
P - Pointed

 

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« Appendix II   |   Appendix IV »
 


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