Diamonds · 3 min read
Princess Cut Diamonds: Why Corner Protection Matters More Than You Think
The sharp 90-degree corners of a princess cut make setting choice and prong placement especially important for long-term wear.
The Structural Nature of Princess Cut Corners
The princess cut is a square or rectangular shape with sharp, uncropped corners, unlike the cropped corners found in radiant or cushion cuts. These sharp corners are visually striking but also represent the most structurally vulnerable points on the stone, since a diamond's hardness does not make it immune to chipping when struck at a thin, pointed edge.
This vulnerability is a durability characteristic rather than something addressed by the GIA Clarity or Color grades, meaning it needs to be considered separately through setting design and careful handling.
Why Setting Choice Is Especially Important
Because of the corner vulnerability, princess cut diamonds are typically set with four prongs positioned specifically to cover and protect each corner, rather than prongs placed along the flat edges as might be used for other shapes. A V-prong design, similar in concept to those used for pear or marquise tips, is commonly used to cup each corner.
Buyers should ask their jeweler whether the proposed setting specifically covers all four corners, since a setting style chosen primarily for aesthetic reasons without attention to corner protection could leave the stone more exposed to chipping over time.
No Formal Cut Grade for Princess Shapes
As with other fancy shapes, GIA does not issue an overall Cut grade for princess cut diamonds, so there is no single letter grade summarizing brightness, fire, and scintillation performance. The GIA report will still include Polish and Symmetry, which relate to facet precision and outline consistency but do not directly measure light performance or corner integrity.
Buyers comparing princess cuts should not assume that Polish and Symmetry grades alone capture everything relevant to the stone's practical durability or visual performance.
Facet Patterns and Variation Among Princess Cuts
Princess cuts can vary in facet count and arrangement between cutters, sometimes featuring different numbers of facets on the pavilion that affect how light travels through the stone. This variation means two princess cuts of similar carat weight and clarity grade can still look different in terms of brightness and sparkle pattern.
Because there is no single standardized facet arrangement required for this shape, visual comparison between candidate stones remains valuable rather than relying on facet count alone as a quality indicator.
Clarity Visibility Considerations
The faceting of a princess cut can sometimes make certain inclusions, particularly those near the corners or culet, more visible than in a round brilliant of similar clarity grade. This is relevant because the corners, being structurally important, are also areas worth checking closely both for visual appearance and durability implications.
Reviewing the GIA clarity plot to see where inclusions are mapped within the stone, particularly near corner areas, can provide more specific information than the overall clarity grade alone.
Practical Recommendations for Buyers
Before purchasing a princess cut, ask the jeweler specifically how the corners will be protected in the chosen setting, request close-up imagery of the corner areas, and review the full GIA report including the clarity plot.
Riakoob advises verifying the GIA report number through official channels and discussing long-term wear habits with the jeweler, since daily wear, such as on an engagement ring, increases the practical importance of corner protection over time.
Further reading & references
Ready to collect?
Every Riakoob piece arrives certified, insured and covered by our 12-month value promise.
Browse the collection