A Must Read Emerald Cut Diamond Buying Guide with Ideal Ratios

A Must Read Emerald Cut Diamond Buying Guide with Ideal Ratios

A Must Read Emerald Cut Diamond Buying Guide with Ideal Ratios

Posted by Sharif Khan on 15th Jan 2021

Complete Emerald Cut Diamonds Buying Guide

 Emerald Cut Diamonds Ratio

Key Takeaways:

  • Emerald cut diamonds are among the most popular diamond shapes. They are different, in the sense, they are classic and antique. They have a step-cut with only 58 facets. If you are looking for something elegant, go for an emerald cut diamond.
  • Since emerald cut diamonds have open facets on the table, it is recommended that you prioritize the clarity grade in emerald cut diamonds. Go for VS2/SI1 at a minimum. 
  • Good square alternative of the emerald cut diamonds are Asscher Cut Diamonds
  • While a length-to-width ratio of 1.3-1.55 is normal, we generally prefer the 1.4-1.5 range. Make sure you know what you prefer. 
  • In terms of cut, a depth of 59-69% and a table of 58-72% is recommended. See the chart below for accurate numbers. 
  • We recommend AGS and GIA as the top labs. Make sure you buy a GIA graded diamond
  • In terms of prioritizing the 4Cs, consider an option like this if you want a pure investment-grade diamond in the high-quality range (example 1). If you want to maximize both quality and carat weight, consider something like this (option 2). This would be a good option if you don't mind compromising slightly on quality in order to maximize the size (example 3). Finally, an option could be to compromise on color in order to maximize cut, clarity, and carat weight when the budget is an issue and you want a big diamond (example 4). 
  • Here is the list of our top websites for buying diamonds and engagement rings online to consider. 


Cutting diamonds into an emerald shape dates back to the 13-14th century when diamonds were beginning to make their way to popular culture. The modern emerald cut diamond has 58 facets, roughly 25 on the crown, 25 on the pavilion, and 8 on the girdle with 3 rows of bottom steps and three rows of top steps. These luminous gems feature step-cut (or trap-cut) because it has rows of facets which is different from other fancy cut shapes. These facets are arranged in rectilinear style parallel to the girdle, typically in a staircase form, hence the name step-cut.

Usually, the corners of diamonds are the weakest points for a typical stone, but emerald cut diamonds beautifully addresses this concern. In addition, the emerald cut diamond features a keel running through the pavilion terminus which is not available in other diamond cuts.

During the Art Deco period, many of the antique jewelry pieces featured step-cut styles which are why today diamond lovers are keen to recapture the aesthetics of that time period. If you love the classic style typically found in antique jewelry, choosing an emerald cut diamond won't be a bad idea.

Analyzing the Cut:

What we find very useful is to play with James Allen's 3D Video Technology and compare the 360-degree videos of different emerald cut diamonds to figure out how the following proportions, as well as different length to width ratios, affect the visual appearance of a stone. Try to play with their filter to get a good sense of what to prioritize in terms of cut. 

Depth %

Poor/Fair: <52.5 or > 80 / 74.6 - 80

Good: 57 - 59 / 71- 74.5

Very Good: 58-61/67.4-70.1

Excellent: 61.3 - 67

Table %

Poor/Fair: <50 or >80/50-52.5 or 75.5-80

Good: 53-57/74

Very Good: 58-61/71

Excellent: 62-70


Poor/Fair: Very Large/Large

Good: Slightly large

Very Good: Medium/Very Small

Excellent: None


Poor/Fair: Ex. Thin – Ex. Thick

Good: Very thin - thick

Very Good: Very thin - slightly thick

 Excellent: Very thin - slightly thick

Length to Width Ratio for Square Shape

Poor/Fair: >1.09 /1.07-1.09

Good: 1.05-1.06

Very Good: 1.00-1.04

Excellent: 1.00-1.04

Length to Width Ratio for Rectangular Shape

Poor/Fair: >1.90 /1.81-1.90

Good: 1.20-1.29/1.63-1.80

Very Good: 1.30-1.38/1.51-1.70

Excellent: 1.39-1.50

James Allen

The chart above serves as a general guideline when evaluating the cut of an emerald cut diamond. The length to width ratio of 1.50 is considered the classic cut for a rectangular-shaped emerald cut diamond. However, the recent trend is towards a more square shape with a ratio of 1.30. Consult with Petra Gems for precise measurements and the length to width ratio of these elegant diamonds.

Evaluating Color:

Just like evaluating the color in other diamond shapes, color in an emerald cut diamond is critical. The higher the color grade, the better. In our experience, many buyers prefer the warmer colors over the colorless colors given the difference in price. In the color spectrum, the warmer colors refer to the near colorless range of G-I color diamonds while the colorless colors refer to D-F color diamonds. The price premium for a lower color grade emerald cut diamond would be significantly lower. Since the body of emerald cut diamonds is large and contains open facets, choosing a higher color grade is recommended when buying an emerald cut diamond.

For more detailed information on the color of the emerald cut diamond, use the table below.

< 0.50 Carat

Poor/Far: >M/ L-M

Good: I

Very Good: G-H

Excellent: D-G

0.51 – 1.0 Carat

Poor/Fair: J-K / >L

Good: I

Very Good: H

Excellent: D-G

1.0 – 2.0 Carat

Poor/Fair: H-I / >I

Good: J/I

Very Good: G-H

Excellent: D-F

>2.0 Carat

Poor/Fair: H-I / >I

Good: H-I

Very Good: F-G

Excellent: D-E


Poor/Fair: Very Strong/Strong

Good: Medium 

Very Good: Faint

Excellent: None

Choosing Clarity:

Since Emerald cut diamonds have open facets, it is recommended to buy a slightly higher clarity emerald cut diamond. Each of our customers has a unique standard for clarity and color. Some of our customers want a flawless diamond while others are perfectly comfortable with inclusions as long as they are not noticeable to the naked eye. GIA provides excellent help with their clarity grades, so you can use it to choose an emerald cut diamond that will meet your standards.

SI1 would be a great balance of price and appearance in an emerald cut. You can also consider buying VS2 for a comparable choice.

< 0.50 Carat

Poor/Far: >I1/ I1

Good: SI1-SI2

Very Good: SI1-SI2

Excellent: FL-VS1

0.51 – 1.0 Carat

Poor/Fair: I1-I3

Good: SI1-SI2

Very Good: VS2-SI1

Excellent: FL-VS1

1.0 – 2.0 Carat

Poor/Fair: I1 / >I1

Good: SI2

Very Good: SI1/ VS2

Excellent: FL-VS1

>2.0 Carat

Poor/Fair: I3/II1

Good: SI2

Very Good: SI1/VS2

Excellent: FL-VS1

Budget Constraints:

The following options are suggested in terms of carat weight, cut, color, and clarity for people with budget constraints.

Excellent Choice:

  • At least 1.0 carats in Weight
  • Very Good to Excellent Polish and Symmetry
  • G or above in color
  • SI1 or above in clarity
  • No Florescence
  • Length/width ratios: 0.95 - 1.05 for square or 1.5 to 1.60 for a rectangular shape

Very Good Choice:

  • At least 0.90 carats in Weight
  • Good to Excellent Polish and Symmetry
  • H or above in Color
  • SI1 or above in Clarity
  • None, faint or medium blue florescence
  • Length/width ratios: 0.95-1.05 for square or 1.45 to 1.65 for rectangular shape

Good Choice:

  • At least 0.80 Carats in Weight
  • Good to Very Good Polish and Symmetry
  • I or above in Color
  • SI1 or above in Clarity
  • None, faint or medium blue florescence
  • Length/width ratios: 0.95-1.05 for square or 1.4-to 1.68 for rectangular shape