Princess cut diamonds are the most popular diamond shape, second only to the Round Brilliant in today’s market. Today the cut is frequently referred to as a “square modified brilliant” on most diamond lab reports.
The Princess cut is a relatively young shape, introduced to the market in the 1970s and patented as the “Quadrillion” diamond. The demand for the princess cut diamond grew quickly, being a clean and modern cut that offers nearly the same brilliance as the popular round brilliant.
Diamond cutters also took nicely to the new, square cut being that it offers the highest yield of rough material of any diamond shape. A round brilliant diamond will typically yield about 40% of rough diamond while a princess cut yields between 80-90% of the rough stone making it a more affordable cut for cutters and consumers alike.
Color
Since princess cut diamonds are brilliant cuts, they offer notably high light return when cut properly. However, it is still recommended that you select no lower than an H or I color for your diamond. Princess cut diamonds with a color grade lower than H or I may appear cloudy or dull, especially if they feature a large table.
Clarity
Because princess cut diamonds are frequently cut to fit the rough stone in order to save as much rough material as possible, most diamond cuts naturally tend to be cut from high quality, clean and well-formed rough stones. Lower clarity princess cut diamonds such as I2s, I1s or SI2s are, therefore, harder to find on the market. Moreover, while these stones may be cheaper, they might not offer the best value. Due to the square shape of the princess cut diamond, any inclusions located in one of the stone's corners may affect the stone’s resistance to chipping. Most diamond professionals recommend searching for princess cut diamonds with a SI1 clarity grade at the very least.
Cut
When it comes to cut, princess cut diamonds can be quite problematic. This is because the GIA, the most widely trusted gemological laboratory, only grades round brilliants and does not grade any other fancy cut diamond including princess cuts. The GIA only grades the polish and symmetry of a princess cut, meaning that table and depth percentages for ideal princess cuts that you find on the web are really only recommendations or guidelines. There are no internationally accepted cut standards for princess cut diamonds in the diamond industry.
The fact that the industry is torn regarding princess cut diamonds stems, once again, from the fact that princess cuts are typically cut to fit the measurements of the rough stone. Due to industry discrepancies, certain gemological laboratories have developed their own standards for grading princess stones. AGS implemented their cut grade for princess cut diamond shapes in 2005. This was the first diamond grading report to include a cut grade for fancy shaped diamonds. The grading is based on specialized light performance software that measures the light performance of each stone submitted to their laboratory, therefore, total depth% and table% measurements do not factor into their grading methods.
Since there is still no industry wide standardized cut grade for princess cut diamonds, most princess diamonds do not meet the top AGS standards for princess cut diamonds. AGS cut specifications call for princess cut stones that are outside of the shape’s conventional parameters and yield significantly less from the rough diamond. In fact, it is estimated that only a very small percentage of princess-cuts are sent to the AGS, and of these, most are higher quality stones. However, AGS’s cut grading system can certainly be used as guidelines for consumers who are concerned with finding an extremely high quality princess cut diamond.
Princess Cut Basic Guidelines
Depth %: 58%-75%
- Princess stones with a depth% lower than 68% are very rare and hard to find. Due to their rarity and their low yield of rough diamond material, they are also quite pricey. We recommend you stay within the 68-75% range for a high quality stone at the best value.
- Note: The depth percentage of a princess diamond is measured differently than that of a round brilliant diamond. The total depth of a round brilliant is a percentage of the average diameter of the stone. In a princess stone, or any other diamond shaped stone, the total depth is a percentage of the lowest diameter of the stone.
Table %: 53%-75%
- For those who prefer smaller tables, look for princess stones with a 68% table or lower. For those who prefer larger tables, look for princess stones with a 70-75% table.
- Diamond cutters seem to fall into two groups regarding princess cuts: there are those who believe Princess cut diamond should be cut with small tables, and there are those who believe that princess cuts can vary in their table size. Again, there is no consensus. It should be noted that princess cut diamonds with small tables are less popular among both diamond cutters and diamond consumers.
The Bottom Line: The above table of basic depth% and table% guidelines for princess cut diamonds are only guidelines.
We believe that many times it just comes down to what you happen to prefer and we recommend you take the time to browse a variety of stones to get a sense of which princess cut depth% and table % you prefer.
