Experts: What is wrong with this Princess stone?

[BrianTheCutter]

On the original sarin girdle plot, the black lines indicate the flat side of the girdle. The red lines that I have added in are the corners and I have noted the indented girdle positions. This is not a problem as this will be covered by the seat of the prong when the stone is set.

 

[BrianTheCutter]

The Expert Selection gives consumers the best value for their money.
It takes a higher degree of expertise and knowledge to select great deals for the money than just to plug in the numbers and select a stone that has perfect proportions and symmetry.

 

[Mara]

Seems like the indented natural can be set under a prong safely, Brian?




The IS images for both seem pretty good compared for most Princesses on the market...but I do agree the 2nd looks better visually in terms of light return. However, both would most likely be better than 90% of what you'd find in a regular retail store!!

Edited to note: We must have posted at the same time, you confirmed the natural can be prong-set.

 

[BrianTheCutter]

Light leakage evaluation should be combined with a live examination, especially for fancies, and that is what we do.
One should remember diamonds are not worn in a static position and the human eyes look at the diamond from different angels which will change the way one would see the stone in a static upright position
Same stone in a tilted position through the ideal loupe

Symmetry is not always a guarantee of the best beauty in fancies - small amounts of light leakage
are good for contrast and character. Ask Serg at MSU I think he would agree!

 

[BrianTheCutter]

The stone not bad!

 

[BrianTheCutter]

The bottom line is that this is a beautiful stone and a great deal for the money when you take all the factors into account.
The pictures speak for themselves

 

[Mara]

Great shots of the stone...it looks like it would be stunning in person. Hmm..tough call

 

[Colored Gemstone Nut]

Nice Photo Brian....It has been said many times before not to judge fancies just by the numbers...

 

[strmrdr]

Thank you for the education Brian.
I had no way of knowing where the thin spot was and I have read a dozen stories about how prone they are to breakage so on the limited amount of information available at that time I will stand by my call at that time.
Would it be possible for you to address further my earlier question about the angles?
...........
Wouldnt the huge angle difference lead to light leakage?
Or is that a non-critical area on princess cuts?
Or are bad cuts just the norm with them?
................

 

[barry]

Correct: Numbers alone don't tell the story. In this case the addtional IS image corroborates the first (despite it's tilt and decreased resolution) and girdle photographs are very informative. The diamond still shows serious leakage (entire left quadrant, right quadrant, and around the culet area); the indented crevice at "a" and the extensive 'natural' right on the point at "b" is extremely dangerous, may result in further fracturing, and should have been addressed and mitigated by the cutter.

Barry
www.superbcert.com

 

[pricescope]

Barry:

----------------
...The diamond still shows serious leakage ...
----------------

As an expert in light leakage, would you care to comment on these images. Which one of these diamonds has more light leakage and why.

Other folks and "cut nuts" are welcome to throw ther 2¢.

"Experts: What is wrong with these Princess stones?"

 

[Mara]

I personally find this pretty interesting and would love Barry and Brian to continue to comment.

 

[FOODIE]

As an Ideal Scope customer, I certainly would like opinion to be ellicited on the Princess Ideal Scope images ... they all look fairly good to me.

 

[barry]

spicola;

I agree with you. I am not at all surprised.
Leonid, I'd like to know why you are singling and calling me out when
One other expert(from Massapequa) made the same comments and observations
above, that I did regarding the Vendor's provided IS image and measurements, but has not been singled out and called front and center by name? Why?

In addition to the leakage, this diamond has more serious problems, and that is the very sensitive and dangerous fractures and naturals noted in Vendor
provided pictures "a" and "b". The same "regulars" that you mention in your other thread this afternoon, spicola, that constantly caution consumers on this forum to be careful about these kind of stones, are all of a sudden conspicuously absent and not addressing this problem. Why?

The consumer who started this thread asked for advice and information.
Based on the provided information, I answered.
Certain parties are obviously intent on steering this thread in a different
direction.

In keeping with the forum moderator's own posted rules and regulations, I will keep my postings civil and respectful

.

Barry
www.superbcert.com

 

[strmrdr]

I know when Im over my head so Im withdrawing from this discussion.
Im here to learn and have a little fun and when I can help someone out to pay back the people that have been helping me.

One final comment:
If I was looking at this diamond I would pass it up because I would be forever worried about it breaking/chipping.
Brian cuts some awesome diamonds and I respect his work on the aca RB diamonds but I dont think he or anyone else could convince me to trust this diamond not to chip or break.
Right or wrong Id pass on it and for me thats my bottom line.

 

[aljdewey]

Withdrawing, too....because I don't know a damn thing about princess stones, and because I'm just worn down from all the acrimony present in the last few days.




Time to refresh and get recentered on the reason for PS in the first place.

 

[pricescope]

Guys, I suggest to keep this topic on educational note and save it from degradation to the level of personal bickering.

Sorry but I'm deleting all the posts that have nothing to do with discussed subjects.

Barry:

----------------
Leonid, I'd like to know why you are singling and calling me out when
One other expert(from Massapequa) made the same comments and observations
above, that I did regarding the Vendor's provided IS image and measurements, but has not been singled out and called front and center by name? Why?----------------

Please revisit Jonathan posts. He hasn't made any conclusion on the level of light leakage after the first ideal-scope image was posted.

My question is not about this particular stone nor about natural dent (I hope other experts will address this interesting issue as well) but merely about reading of the ideal-scope images (for princess shaped stones in particular) and deriving conclusions on the level of the light leakage.

Hope experts and cut enthusiasts will share their opinions on this subject.

 

[pricescope]

I found these stones at GOG and ran Diamond Calculator for SRN files.

No link
1 - http://www.goodoldgold.com/princess_0_84ct_f_vvs2.htm
2 - http://www.goodoldgold.com/princess_1_02ct_f_vs2.htm
3 - http://www.goodoldgold.com/princess_0_81ct_f_vs2.htm
4 - http://www.goodoldgold.com/princess_0_89ct_h_vs1.htm

 

[pricescope]

I will post more data separately, just wanted to demonstrate that based on ideascope image alone it is impossible to evaluate how strong light leakage is.

Note DiamCalc estimates higher leakage for diamonds with almost no white on IS pictures while #2 with some white has less leakage.

We have to understand what we see in IdealScope – human perception of the light return distribution. IS doesn’t measure it. If you see some red, pink, white, grey or black, it is just human eye perception.

In general, viewer cannot tell exactly how much light is leaking and the level of the light return. When we see some white/gray/pale-pink in idealscope it doesn’t mean diamond won’t return light from these areas. Human eyes adjust to see red and white in greater contrast that it really is – eye adaptation feature. It works as logarithm. If human eye sees 50% less red in reality this “leakage” area still reflects over 75% of light.

We only can compare different diamonds if they are viewed (photographed) in the same conditions. Still it cannot guarantee the right conclusion as I'll show on more examples.

I understand peoples desire to have an ultimate tool to find well cut diamond. Ideal-Scope is a great tool but once you weed out bad candidates other factors should be considered.

Similar to HCA < 2. Is diamond with HCA=2.5 ok or it is better to pass? Is diamond with HCA = 1 better than HCA = 2?...

 

[Garry H (Cut Nut)]

It is not quite that bad Leonid - when you can see the stones with your eye in a side by side situation - we are comparing photo's that were obviously shot with varying lighting, with or without touching up.
When you have a parcel of stones then it is easy to use the ideal-scope to pick the best and worst light return.

But this is an excellent example of why we need a standardised lighting / photo system.

http://www.cutstudy.com/cut/english/optical/index.htm

Anyone seriuosly interested in this topic needs to spend an hour with a printed copy of this AGS article on the MSU site.

I have found examining princess cuts in a black box with an ideal-scope does work quite well.