How many chevrons in a princess cut?

[LegacyJoe]

I notice there are different number of chevrons on princess cuts or modified square brilliants. For a 2 carat (about 7mm) stone is there a preferred number?

 

[Paul-Antwerp]

Hi Joe,

Preference in this case is rather personal, I think, although it probably also depends on which setups one had the ability of seeing in person.

Starting from a traditional average of 3 or 4 chevron-lines, there are basically two schools in cutting. The traditional school aims to put as many chevrons as possible. Considering cut-quality, I am of the opposite school and have reduced the number of chevron-lines to two. This clearly improves in my opinion the observed scintillation and fire.

All in all, considering the difficulty of assessing a princess-cut online, I would suggest to try and see as many as possible in person.

Live long,

 

[yssie]

Paul, can you go into your comment a bit more? What is the benefit of four chevrons over two in the market - why would cutters want to produce these stones?

 

[Paul-Antwerp]

Cutters have generally approached the princess from the perspective of weight-retention. Hardly any of the traditional cutters of princess-cuts has any idea of what makes a princess tick cut-quality-wise.

As a result, they often left little room for a crown, keeping that very flat and boring. In a good rough crystal, this was the starting point for a high final weight on two stones, with a high diameter on both stones.

In order to at least get some 'action' in the stone with the flat big-table crown, more chevron-lines in the pavilion looked better. This translated into a general feeling of more chevrons being better, while the actual result was that most princess-cuts are not well-cut. Also, more chevron-lines gave more possibility of retaining weight in the pavilion with a huge difference in angle between the two main pavilion-angles.

In other words, the traditional feeling that more chevron-lines is better is based upon the incorrect initial approach of a princess. It is comparable to using low-quality ingredients for a dish and then trying to hide the lack of taste by adding a rich sauce.

Live long,

 

[Fly Girl]

LegacyJoe - I hope you will take a look at the Crafted by Infinity princess cuts. I have seen them in person and they are gorgeous. Generally, I don't much like princess stones, but I'm a fan of Paul's products.

 

[yssie]

Thanks Paul. I see re. weight retention, too.

 

[ChunkyCushionLover]

Cutters have generally approached the princess from the perspective of weight-retention. Hardly any of the traditional cutters of princess-cuts has any idea of what makes a princess tick cut-quality-wise.

As a result, they often left little room for a crown, keeping that very flat and boring. In a good rough crystal, this was the starting point for a high final weight on two stones, with a high diameter on both stones.

In order to at least get some 'action' in the stone with the flat big-table crown, more chevron-lines in the pavilion looked better. This translated into a general feeling of more chevrons being better, while the actual result was that most princess-cuts are not well-cut. Also, more chevron-lines gave more possibility of retaining weight in the pavilion with a huge difference in angle between the two main pavilion-angles.

In other words, the traditional feeling that more chevron-lines is better is based upon the incorrect initial approach of a princess. It is comparable to using low-quality ingredients for a dish and then trying to hide the lack of taste by adding a rich sauce.

Live long,

Paul,

I read your really informative article https://www.pricescope.com/journal/ags_new_cutgrading_princesses_first_experience which differentiates between cutting for 'action' and cutting to save weight in a princess. Your posts in this thread answer Yssie's question really well but I think the OP had a different question in mind.

You have explained really well the difference between well cut and cut for weight in overall proportions. However in either type it is possible to find examples with 2, 3 or 4 chevron pavilions.

A well cut princess cut can have excellent 'action' with any of the three pavilion styles.

Based on the PY AGS research presentations and my own simulations(assuming perfect optical symmetry):

4 chevron has the potential for the fastest scintillation( largest number of sparkles) and brightness. It has the smallest average virtual face(size of flashes) and will have the least potential to show fire(colored light)

2 Chevron has the slowest scintillation(fewest number of sparkles), and the potential for darker more contrasty areas. It has the largest average virtual facet size (size of flashes) and will have the greatest potential to show fire(colored light).

3 Chevron is in between the two in potential of all three properties.

I would have trouble advising a novice consumer to equate the number of pavilions with the quality of cut. The choice of number of pavilions becomes a tradeoff of larger more infrequent flashes versus smaller more frequent flashes.

 

[Paul-Antwerp]

CCL,

You are right if you are assuming perfect optical symmetry.

However, such princess-cuts are rare, extremely rare.

Live long,

 

[ChunkyCushionLover]

CCL,

You are right if you are assuming perfect optical symmetry.

However, such princess-cuts are rare, extremely rare.

Live long,

It is my understanding and shared opinion that deviations from perfect optical symmetry lower the average virtual facet size and number of observable virtual facets but do not change the general trends listed above. It would seem intuitive to me that starting with smaller physical facets will yield smaller virtual facets to begin with and that these facets will be further broken up into even smaller pieces if not aligned symmetrically.

On pricescope we are a microsphere where extremely rare is common.
We have all three types of princess cut designs being offered by PS vendors and each was specifically designed with light performance in mind.

Infinity (two chevron)
Solasfera and BGD Signature (three chevron)
ACA (four chevron)

 

[stone-cold11]

WF has a range of chevron design or maybe they are fine tuning/experimenting?

2 chevrons. http://www.whiteflash.com/loose-diamonds/princess-cut-loose-diamond-2231076.htm

3 chevrons. http://www.whiteflash.com/loose-diamonds/princess-cut-loose-diamond-2231078.htm

Also, do not see a 4 chevron for a smaller than 1c and 2 chevron for a stone larger than 1c, so probably balance with real virtual facet size?

 

[Paul-Antwerp]

Bottom-line, instead of only focusing on the number of chevrons, attention should probably go first to the total set-up of the princess, like in any shape.

If that has been approached with proper attention, one can look at the differences caused by the different number of chevrons, and at this level, one might say that this is a taste-factor.

The main problem in princess-cuts actually is the rarity (even on PS) of the well-cut princess-cuts.

Live long,

 

[ChunkyCushionLover]

Bottom-line, instead of only focusing on the number of chevrons, attention should probably go first to the total set-up of the princess, like in any shape.

If that has been approached with proper attention, one can look at the differences caused by the different number of chevrons, and at this level, one might say that this is a taste-factor.

The main problem in princess-cuts actually is the rarity (even on PS) of the well-cut princess-cuts.

Live long,

Excellent post and I am in total agreement.

 

[ChunkyCushionLover]

WF has a range of chevron design or maybe they are fine tuning/experimenting?

2 chevrons. http://www.whiteflash.com/loose-diamonds/princess-cut-loose-diamond-2231076.htm

3 chevrons. http://www.whiteflash.com/loose-diamonds/princess-cut-loose-diamond-2231078.htm

Also, do not see a 4 chevron for a smaller than 1c and 2 chevron for a stone larger than 1c, so probably balance with real virtual facet size?

That is a very interesting trend and quite opposite of what I would expect if truly representative of their rough planning decisions instead of the more likely just limited selection of ACA princess cuts.

Theoretically one would think the larger carat size would be preferred for the 4 facet variety, as the average VFs are larger and more of the smallest ones would then fall into the size range that can be perceived by the human eye.

I would be very interested to know what DimondBob (Bob Hoskins) or Allison has to say on this topic and I'm going to start a topic on it.

 

[anitabee]

i have a princess cut. how can i tell how many chevrons mine has? is it indicated in the grading report by the inclusion plotting diagram of the stone's bottom?

do you have to physically look at the bottom of the stone. mine's already set and i've tried looking through the side. it's hard to tell.

 

[stone-cold11]

Yap, in the report, pavilion view of the clarity map.