Online Diamond Education: Diamond Value
Recommended Ideal Cut Proportions
One of the grades affecting a diamond's price is the cut. Each type of
diamond has its own specifically cut proportions. Those measurements are
relational to the diamond price. The chart below lists various diamond types,
their characteristics and the proportions from ideal to poor.
Diamond Cut Grade
IDEAL
PREMIUM
GOOD
FAIR-POOR
Difference in Value
TYPE: ROUND BRILLAINT
TABLE %
53-57
58 - 61
61 - 64
65 +
DEPTH %
62.5-60.6
62.9-59.5
63.9-57
64 + or 57 -
POLISH
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
CULET
None - Very Small
None - Small
None - Small
Medium - Large
GIRDLE
Thin - Medium
Thin - Thick
Very Thin - Thick
Extremely Thin - Very Thick
TYPE: SQUARE CUTS - PRINCESS, RADIANT,
EMERALDS
TABLE %
65-70
71-75
76-84
85 +
DEPTH %
65-71
71-75
76-80
80 +
POLISH
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
CULET
None - Very Small
None - Small
None - Small
Medium - Large
GIRDLE
Thin - Medium
Thin - Thick
Very Thin - Thick
Extremely Thin - Very Thick
TYPE: ELONGATED CUTS - RADIANTS,
EMERALDS
TABLE %
65-69
70-74
75-80
80 +
DEPTH %
64-69
63-71
72-78
79 +
POLISH
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
GIRDLE
Thin - Medium
Thin - Thick
Very Thin - Thick
Extremely Thin - Very Thick
CULTE
None - Very Small
None - Small
Small - Medium
Medium - Large
LEGNTH/WIDTH RATIO
1:1.35-1:1.42
1:1.29- 1:1.49
1:1.20-1:1.6
Subjective
TYPE: PEAR
LEGNTH TO WIDTH
1.45:1-1.6:1
1.35:1-1.7:1
1.25:1-1.8:1
1.2:1-2:1
BOW TIE EFFECT
None - Minimal
Minimal - Average
Average - Significant
Significant
DEPTH %
59-63
57-65
55-68
50-75
TABLE %
55-58
53-61
50-64
48-69
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
GIRDLE
Thin - Medium
Thin - Thick
Very Thin - Thick
Extremely Thin - Very Thick
CULET
None - Very Small
None - Small
None - Small
Medium - Large
TYPE: MARQUIS
LEGNTH TO WIDTH
None - Minimal
Minimal - Average
Average - Significant
Significant
BOWTIE EFFECT
1.95:1-2.05:1
1.8:1-2.2:1
1.65:1-2.3:1
1.5:1
DEPTH %
59-63
57-65
55-68
50-75
TABLE %
55-58
53-61
50-64
48-69
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
GIRDLE
Thin - Medium
Thin - Thick
Very Thin - Thick
Extremely Thin - Very Thick
CULET
None - Very Small
None - Small
None - Small
Medium - Large
TYPE: OVAL
LEGNTH TO WIDTH
1.35:1-1.42:1
1.3:1-1.5:1
1.25:1-1.65:1
1.15:1-1.9:1
BOWTIE EFFECT
None - Minimal
Minimal - Average
Average - Significant
Significant
DEPTH %
59-63
57-65
55-68
50-75
TABLE %
55-58
53-61
50-64
48-69
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
SYMMETRY
Excellent - Very Good
Verygood - Good
Good
Fair - Poor
GIRDLE
Thin - Medium
Thin - Thick
Very Thin - Thick
Extremely Thin - Very Thick
CULET
None - Very Small
None - Small
None - Small
Medium - Large