Princess Cut Diamonds | Ideal Proportions, L/W Ratio Guide

The key to optimizing a princess cut diamond's brilliance is achieving a well-balanced cut that avoids excessive depth or shallowness. 

We advise buyers to avoid a princess cut diamond whose depth percentage is smaller than its table percentage.

Princess cut diamonds do not receive an official cut grade in GIA reports; however, AGS assigns them a cut grade.

We recommend a princess cut with a total depth ranging from 68% to 70% and a table of 62 to 69%, with a permissible tolerance of 5%. Additionally, make sure the diamond's polish and symmetry are graded as very good at a minimum.

This proprietary high-definition 3D video with 40X Magnification is helpful for a detailed visual inspection of how specified proportions impact a diamond's appearance. It can also aid in identifying inclusions, particularly black crystals. Experimenting with the available filters on the platform is also beneficial in identifying the best options within a given budget range.

The chart below is critical when evaluating the cut quality of a princess cut diamond:

The image below shows a 1 carat square and rectangular princess cut diamonds for reference. A rectangular princess cut diamond might be the best choice for individuals with long, slender fingers.

H or I Color in a princess cut diamond will give you more value for the money, although the higher the color grade, the better the diamond. When evaluating the color of a princess cut diamond, it is important to look for a stone that does not have a visible yellow tint. Hence, buyers will be better off if they do not choose a color grade lower than G, H, and/or I.

Spending additional money to buy a colorless princess cut diamond, i.e., those graded as D, E, and/or F, is not essential. Unlike I or J colors, G and H color diamonds are also high-quality stones and should be a top choice for people with a limited budget.

Fluorescence can negatively influence the quality of a diamond and is mainly evaluated against a diamond's color. In short, avoiding it in colorless diamonds is recommended, while it might be a positive factor in near colorless or faint color diamonds. This is because blue is a complementary color to yellow; blue fluorescence can make faint diamonds whiter than their actual color. For additional insights, refer to our guide on diamond fluorescence.

The table below could be helpful for an in-depth examination of color in princess cut diamonds:

Princess cut diamonds are famous for their ability to exhibit significant brilliance and sparkle. In addition, their brilliant facets make their inclusions less visible.

Although princess cut diamonds with clarity lower than SI1 are rare, buyers may still find their dream princess cut diamond if they focus on buying one with VS1, VS2, SI1, and/or SI2 clarity grade.

When buying these sparkling diamonds, avoid ones with large inclusions near their corners, making the diamond susceptible to chipping.

Use the following chart as a general guideline when selecting the clarity grade of a princess cut diamond based on its carat weight:

In addition to the well-known 4Cs, it is imperative for buyers to be familiar with the following key aspects of a princess cut diamond grading report or certificate, as highlighted in the image below:

Watch HD Video of this Diamond.

Measurements: This holds significance as it provides the buyer with information about the surface size of the diamond, indicating how large the diamond will appear in millimeters. It can also be used to determine the length-to-width ratio by dividing the length by the width (in the above case, it is 6.41/6.25=1.02).

Fluorescence: This should be regarded as the 5th C. Given that the color is G, avoiding fluorescence or selecting faint fluorescence is the optimal choice in this specific example. However, medium blue fluorescence is not as concerning as strong blue fluorescence.

Comments: This section will display factors related to clarity and highlight whether a diamond has undergone clarity enhancement utilizing methods like laser drilling or color enhancement. Additionally, be attentive to comments such as "clarity grade based on clouds," which is a worrisome indicator within clarity grades of VS2 and below. The laser inscription of the report number on the girdle is positioned above the comments section, offering an optional service for added verification.

Proportions: This chart is crucial for assessing a diamond's cut. Specifically, pay attention to the table percentage (72% in the example—excellent), depth percentage (71.5%—excellent), girdle (medium to slightly thick—excellent), and culet (none—excellent).

Clarity Characteristics: This section will indicate the types of inclusions and their respective locations. It can help buyers avoid diamonds with visible inclusions at the center. These details are also useful for correlating the report with the diamond, as these inclusions serve as the diamond's unique birthmarks.

Consider the following four scenarios while shopping for a princess cut diamond. This is how buyers typically prioritize the 4Cs.

Scenario 1: A buyer's priority is getting the highest color, clarity, and cut grade for any carat weight (often called "investment" grade diamonds). The perfect fit here would be flawless to VVS, D-E color, GIA graded, and no fluorescence.

Scenario 2: In this category, the shopper is still interested in a high-quality diamond but wants to get a bigger stone (we call these "high circulation" and "high-value" stones because they are the most traded online). Thus, they may go as low as VS clarity and G/H color diamond, very good to excellent cut, medium blue fluorescence, and 1.5 carats instead of 1.

Scenario 3: In this scenario, the buyer is willing to go as low as possible to get an eye-clean stone with a decent color and the largest possible size. Therefore, they choose a 2 carat, SI1/SI2, up to J color, and strong blue fluorescence and are willing to consider IGI or HRD certification. Understanding how to assess inclusions in a diamond is important when considering this category. Knowing which inclusions to avoid and which could work in your favor can make all the difference.

Scenario 4: The shopper knows that they must compromise heavily on 1C to maximize the other 3Cs. In this category, we usually recommend giving up color for maximum cut, carat weight, and clarity quality. The stone will look slightly yellowish (a warm color might be your preference) but will still have optimal brilliance and fire because of the cut, high clarity, and big size.

Princess Cut Diamond Options for Buyers with Budget Constraints:

Excellent Choice

• Weight of at least 1.10 carat
• Very good to excellent polish and symmetry
• G or above in color
• Clarity of SI1 or higher
• No fluorescence
• Length/width ratios: 1-1.05 for square or 1.2-1.3 for rectangular shape

Very Good Choice

• At least 1.00 carats in weight
• Good to excellent polish and symmetry
• H or above in Color
• Clarity of SI1 or higher
• None, faint or medium blue fluorescence
• Length/width ratios: 1-1.05 for square or 1.2-1.3 for rectangular shape

Good Choice

• At least 0.90 carats in weight
• Good to very good polish and symmetry
• I or higher in color
• Clarity of SI2 or higher
• None, faint or medium blue fluorescence
• Length/width ratios: 1-1.05 for square or 1.2-1.3 for rectangular shape

Are princess-cut diamonds famous?

Yes, they are popular among shoppers looking for alternative round cut diamond options. Although oval and cushion cut diamonds have been trending higher than princess cut diamonds lately, the latter is still prevalent. 

Which one is better: a square or rectangular princess cut diamond?

It depends on your taste; we are equally divided when determining which is better. If you have thin fingers, rectangular might be the way to go. They will also look bigger than squares and might be slightly pricier. However, square shapes are generally more popular; you will see more square options on the market than rectangular ones.

What is the difference between princess cut and radiant cut diamonds?

Radiant cut diamonds generally have cut corners and slightly different faceting structures in terms of cut. Follow our guide on radiant cut diamonds for detailed information.