1 ct princess diameters

[researcher]

A quick search on PS for 1 ct princess cut stones reveals a wide variation in diameters. I was therefore wondering what "standard" range the diameters of well-cut stones would fall into. I realize that the "acceptable" depth and table combinations for very good to "ideal" cut princess stones will lead to a fairly wide range of numbers, but there are so many people that constantly ask for the best spread for fancies that I think it would be nice to have a basic number to provide. My guess is somewhere in the 5.4-5.7mm range for 1 ct princess stones, but I''m not an expert. Anyone agree/disagree with this range?

 

[researcher]

No one has any thoughts on this? Write down any random thoughts or guesses--well, any that relate to determining the "standard" diameter of a 1 ct princess....

 

[valeria101]

There is no standard for size...

The description of the standard branded radiant includes size (area) among the characteristics of the cut, but I do not know any other description of a standard cut that doe sthat.

You may find it interesting that there is no sraightforward relationship between the AGA cut categories for the princess cut and size (for example, one of thse shallow 4B would be substantially larger than a 1A...).

What's the use of a "standard size" ?

 

[researcher]

I continually come across threads wherein people are asking about the spread of a princess cut or the average/standard diameter of a well-cut stone. Naturally, as a result of my participation on this forum I began to tell people the standard response--there is no standard for fancy shapes. However, there have to be SOME trends in terms of cut. They don't have to be as close as those for rounds, but excluding stones that don't fit into the 1A-1B categories for table and depth there might just be a range that we can tell people. This was just one of the most frustrating things for me when I first started my search (the lack of specifics for princesses), so I was hoping we could come up with a--for lack of a better word--general guideline for the spread of 1 ct princess stones. There will always be exceptions, but it's nice to have a general idea

Thanks for your response!

 

[valeria101]

It is easier to set a ref. for size... than for the sum total of the cut.

It would be the total depth and girdle width that determine size for each weight, so... you may just want to pick up a refference depth (say 70%) and "medium" girdle, come up with the typical surface area for that (since not all stones are square) and that's that.

The same logic could be applied with any formula for approximating weight, such as the one cited on the NiceIce site (Link). This one gives 5.6mm for the side of a 1 carat princess cut of 70% depth... which holds pretty well. The next tenth of a mm (and I really think that's not very significant at all) would bring depth to 64% - definitely not "usual". SO I would keep that 5.6 in mind.

All in all, it seems to make sense and give a simple formula like the one at Niceice - everyone could play with it and the AGA charts at leisure

 

[researcher]

So, if people are trying to figure out whether the diameter of the stone they're looking at is in the right ballpark they can use the following formula:

[(Carat weight of a princess stone to the power of 1/3)]*5.6

I still think it's a good idea to consider 1 ct diameters in the range of 5.4-5.7mm instead of just looking at 5.6mm because of the differences in depth etc., but I think this thread is a good start for people who want to know more about determining the actual size and an "expected" spread/diameter. This is in no means meant to lead people to believe there's a right or wrong diameter for a given carat weight, but they will at least have a better idea of how their stone compares (in addition to just looking at the L/W).

Thanks for your input!

 

[HollyGo-Lightly]

This is what I have been asking for the longest! Thanks for posting it seperately and seeing if anyone will bite...I wish people did a cut study on Princess stones, as they seem to be the neglected step-child of the diamond world!

Thanks researcher!

 

[researcher]

No problem. I think it's important, as I said before, to NOT sacrifice cut, but that it's fine to determine the "standard" diameter of a certain size for ideal cut stones. This way, people can better tell if their stone has a good spread for stones with amazing cuts. Glad this helps!

 

[researcher]

BTW, if you go to:
http://members.aol.com/johnp71/scicalc.html

You can enter the formula in as:

[Power(Carat weight of your stone, 1/3)]*5.6

and it will give you the expected diameter for a particular carat, assuming the average diameter of a well-cut princess stone is 5.6 (I also think you should plug in 5.4-5.7).