When we look at the proportion of the diamond, we not only look at the ratio between its width and depth but various other characteristics namely depth %, girdle and table%. The sparkle and brilliance that you get out of the diamond depends greatly on these factors that affect the proportion. Below we have the descriptions of the ratio, depth percentage, girdle and table size and a table detailing the ideal proportions you should look for with each type of shape as mentioned above.
(Note: If there are some parts of the diamond you are still not familiar with, please refer back to the diamond’s anatomy page)

Depth Percentage – The ratio of total depth (table to girdle) as compared to total diameter of the diamond. A good depth percentage, which is not too depth nor shallow can maximize the brilliance of the diamond.

Table Percentage – The ratio of table witdh as compared to total diameter of the diamond.

Ratio - The ratio of  LENGTH (longest side) to WIDTH (shortest side) from diamond serface. Round diamond’s ratio is closed to one. For marquise shape’s ratio will definitely more than 1.

Girdle – The outer edge of diamond where the top and bottom of the stone meet. If the girdle too thin, it tends to chip; A thick girdle not only waste of your carat but also reduce the brilliance!

Round shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	59.0% – 61.0%	58.5% – 58.9% or 61.1% – 62.5%	58.0% – 58.4% or 62.6% – 63.0%	Outside the ranges
Table %	52.4% – 57.5 %	57.6% – 59.5%	59.6% – 62.5%	Outside the ranges
Ratio	1.00	1.001 – 1.005	1.006 – 1.01	Outside the ranges
Girdle	Medium, Facted	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges

Marquise shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	56.0% – 72.0%	52.0% – 55.9% or 72.1% – 75.0%	48.0% – 51.9% or 75.1% – 78.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 61.0%	61.1% – 62.5%	Outside the ranges
Ratio	1.95 – 2.05	1.80 – 1.94 or 2.06 – 2.10	1.70 – 1.79 or 2.11 – 2.15	Outside the ranges
Girdle	Medium, Faceted	Thin to Thick, Faceted	Very Thin to Very Thick, Faceted	Outside the ranges

Oval shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	56.0% – 65.0%	55.0% – 55.9% or 65.1% – 67.5%	54.0% – 54.9% or 67.6% – 70.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 61.0%	61.1% – 62.5%	Outside the ranges
Ratio	1.45 – 1.55	1.35 – 1.44 or 1.56 – 1.60	1.30 – 1.34 or 1.61 – 1.65	Outside the ranges
Girdle	Medium, Facted	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges

Pear shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	56.0% – 65.0%	55.0% – 55.9% or 65.1% – 67.5%	54.0% – 54.9% or 67.6% – 70.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 61.0%	61.1% – 62.5%	Outside the ranges
Ratio	1.55 – 1.65	1.45 – 1.54 or 1.66 – 1.70	1.35 – 1.44 or 1.71 – 1.75	Outside the ranges
Girdle	Medium, Facted	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges

Heart shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	56.0% – 65.0%	55.0% – 55.9% or 65.1% – 67.5%	54.0% – 54.9% or 67.6% – 70.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 61.0%	61.1% – 62.5%	Outside the ranges
Ratio	1.00 – 1.05	1.06 – 1.10	1.11 – 1.20	Outside the ranges
Girdle	Medium, Facted	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges

Radiant shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	60.0% – 63.0%	59.0% – 59.9% or 63.1% – 65.0%	58.0% – 58.9% or 65.1% – 70.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 65.0%	65.1% – 75.0%	Outside the ranges
Ratio	1.00 – 1.20	1.21 – 1.25	1.26 – 1.35	Outside the ranges
Girdle	Medium	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges

Asscher shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	59.0% – 65.0%	58.0% – 58.9% or 65.1% – 67.0%	57.0% – 57.9% or 67.1% – 70.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 65.0%	65.1% – 70.0%	Outside the ranges
Ratio	1.00 – 1.05	1.06 – 1.09	1.10 – 1.12	Outside the ranges
Girdle	Medium	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges

Emerald shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	60.0% – 63.0%	59.0% – 59.9% or 63.1% – 65.0%	58.0% – 58.9% or 65.1% – 70.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 65.0%	65.1% – 75.0%	Outside the ranges
Ratio	1.35 – 1.55	1.30 – 1.54 or 1.56 – 1.65	1.25 – 1.29 or 1.66 – 1.70	Outside the ranges
Girdle	Medium	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges

Princess shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	60.0% – 75.0%	59.0% – 59.9% or 75.1% – 77.0%	58.0% – 58.9% or 77.1% – 79.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 65.0%	65.1% – 75.0%	Outside the ranges
Ratio	1.00 – 1.05	1.06 – 1.10	1.11 – 1.15	Outside the ranges
Girdle	Medium	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges

Cushion shape diamond Proportions
	Excellent	Very Good	Good	Fair / Poor
Depth %	59.0% – 65.0%	58.0% – 58.9% or 65.1% – 67.0%	57.0% – 57.9% or 67.1% – 70.0%	Outside the ranges
Table %	53.0% – 57.9 %	58.0% – 65.0%	65.1% – 75.0%	Outside the ranges
Ratio	1.00 – 1.20	1.21 – 1.25	1.26 – 1.35	Outside the ranges
Girdle	Medium	Thin to Thick, Facted	Very Thin to Very Thick, Facted	Outside the ranges