Super ideal proportions and symmetry but Ideal Scope shows light leakage - why!

[rbank]

Hi All! First time posting on Price Scope, but been an avid follower for quite some time! I've read dozens of posts and articles but still have a burning question that I can't seem to figure out. Hoping folks can help

I have a diamond which has proportions seemingly in the super ideal sweet spot, and shows a fairly clean Hearts & Arrows pattern. However, when viewed with an Ideal Scope, it shows more light leakage than I'd expect for such a diamond (almost like a ring of fire). I can't figure out if I'm not using the Ideal Scope correctly or if I'm missing something else that may be causing the less than brilliant light performance?

Only thing I could think of, may be the variance between each individual facet's measurements. However, if a stone shows excellent symmetry and H&A, is it safe to say that the variance between individual facets can't be that much?

Would also love to hear your thoughts on this stone! Thanks in advance!!

Note that the last photo is a quick analysis I managed to get done while at a gem fair using a Sarine DiaMension type system (instead made by OGI Systems) to get some additional rough analysis. I didn't have a great chance to clean the stone exactly perfectly, nor center it perfectly, so measurements may be a tad off.



Diamond Details:
Carat: 2.33
Color: G
Clarity: VVS2
Cut: Excellent
Symmetry: Excellent
Polish: Excellent
Dimensions: 8.51-8.54x5.26
Pavilion Angle: 40.9
Crown Angle: 34.4
Table: 56%
Depth: 61.7%
Girdle: Thin-Medium
Culet: Pointed
Florescence: None
Star Facets: 51%
Lower Girdle Facets: 77%
Crown Depth: 15.0%
Pavilion Depth: 43.0%

 

[OoohShiny]

Welcome to the forum

Nice looking stone and great specs!

Well done on finding someone with a scanner - that's really useful for understanding cut accuracy and consistency, which is hard when GIA and AGS don't grade MMDs either fully or at all.

Check out the variances in the Measured Values column of the scanner results:

Crown Angle - 34.2 to 35.0 degrees
Pavilion Angle - 40.7 to 41.0 degrees
Lower Half Length - 73.9 to 79.4 percent

That is quite a wide range on both the crown angle and lower halves. The crown angles all fall within the 'superideal' range, but we don't know if the steeper crown sections are paired with the shallower pavilion angles (which we'd want) or the deeper pavilion angles (which we wouldn't want).

I'm not an expert but it could be one side of the stone is shallow and the other side is deep, which could explain why half the under-the-table section on the arrows image is a different colour to the other half. (Although it could just be lighting and/or a slightly tilted stone.)


Look at the Lower Half Lengths as well - GIA rounding is a joke if one can be under 74 and another can be over 79, but the GIA figure is 75%!


Overall, though, and IMVHO, I think you've done well for an MMD, and it's probably on par with a decent GIA XXX If it looks nice 'in real life' and under a scope is the only time it has issues, don't worry about it, I reckon!

 

[Gohsef]

Thanks for the quick reply! Yeah - looks like the variance in crown/pavilion on each of the individual facets might be the culprit. Attached is a picture of a second more detailed scan which shows the individual facet measurements.

Am I correct to pair the crown angle and the pavilion angle of the same facet when considering the light performance?

 

[OoohShiny]

Thanks for the quick reply! Yeah - looks like the variance in crown/pavilion on each of the individual facets might be the culprit. Attached is a picture of a second more detailed scan which shows the individual facet measurements.

Am I correct to pair the crown angle and the pavilion angle of the same facet when considering the light performance?

You appear to have signed up again with a new/different user name?

AFAIK the pavilion facet under a given crown facet should be considered together, so you'd need to look at the numbers for 1 together, number for 2 together, etc.

(I may be wrong.)

 

[denverappraiser]

Idealscopes are very particular about the positioning of the stone in terms of level, centering, and getting the girdle plane even with the opening of the cone. The big companies here that post photos put a LOT of effort into those pictures. Looking through one 'live' is a different sort of experience.

 

[Gohsef]

Thanks for all the pointers! Much appreciated!

I happened to be at the Jewellery fair and came across a nice comparable natural diamond at a pretty good price. So I ended up snatching it up. Given the table leakage of the MMD under ideal scope, I decided to give it a miss. Hope I made the right choice . Certificate below in case anyone has any thoughts!

And apologies about the newb mistake with multiple accounts. I noticed I originally posted with my old account which was saved in my browser, whereas this account is actually my Price Scope Premium account d’oh! Unfortunately looks like there’s no way to edit posts.

 

[Elsa2006]

Thank you for this post. I have been similarly curious.
The specs on the MMD I am still considering (please see below) are similar to the one you were considering.

The listed values fall within the ideal range. However, when I looked at it under an ASET scope: (1) it was difficult to align all the arrows into view (I didn't have similar difficulties with a comparable stone) and (2) more importantly, there was that ring of death light leakage under the table.

Related to what denverappraiser has mentioned above, perhaps my lack of experience positioning the stone had something to do with it. But there definitely was some light leakage under the table as I was able to see my skin color directly underneath the ring of death.

Aside from a gem fair, where can someone get such a comprehensive analysis done to evaluate the crown/pavilion angle variations among the different facets?


------------------------------------------------------

REPORT CITY DATE ANTWERP, November 25, 2018 (IGI)
DESCRIPTION: LABORATORY GROWN DIAMOND
SHAPE AND CUT: ROUND BRILLIANT
CARAT WEIGHT: 3.03 Carats
COLOR GRADE: F
CLARITY GRADE: VS 2
CUT GRADE: IDEAL
POLISH VERY: GOOD
SYMMETRY: EXCELLENT
Measurements: 9.28 - 9.33 x 5.72 mm
Table Size: 56.5%
Crown Height: 15% - 34.5°
Pavilion Depth: 43% - 40.9°
Girdle Thickness: MEDIUM TO SLIGHTLY THICK (FACETED)
Culet: POINTED
Total Depth: 61.5%
FLUORESCENCE: NONE
COMMENTS: The laboratory grown diamond described above is classified as Type IIa. Laserscribe on Girdle: "LAB GROWN LG 341802157"
------------------------------------------------------

Thanks for the quick reply! Yeah - looks like the variance in crown/pavilion on each of the individual facets might be the culprit. Attached is a picture of a second more detailed scan which shows the individual facet measurements.

Am I correct to pair the crown angle and the pavilion angle of the same facet when considering the light performance?

by denverappraiser

 

[OoohShiny]

Aside from a gem fair, where can someone get such a comprehensive analysis done to evaluate the crown/pavilion angle variations among the different facets?

You'll need to find someone with a SARIN scanner (IIRC?) or the same scanner as mentioned above, I reckon.

 

[denverappraiser]

Aside from a gem fair, where can someone get such a comprehensive analysis done to evaluate the crown/pavilion angle variations among the different facets?

Quite a few independent appraisers offer this service. I do, for example. I'm curious though. I don't think I've ever heard of anyone offering it at a 'gem fair' because it's sort of time-consuming and takes some specialized equipment. Working gem shows is all about doing things quickly. Can you describe what you mean and where you saw it?

 

[Elsa2006]

The original post mentioned that the analysis was done "at a gem fair using a Sarine DiaMension type system (instead made by OGI Systems)".

I tried to find a Pricescope recommended appraiser but the zip code search did not yield anything in my area. New to the diamond buying/appraising process, please let me know if you have a suggestion on how best to find an unbiased appraiser.

Quite a few independent appraisers offer this service. I do, for example. I'm curious though. I don't think I've ever heard of anyone offering it at a 'gem fair' because it's sort of time-consuming and takes some specialized equipment. Working gem shows is all about doing things quickly. Can you describe what you mean and where you saw it?

 

[OoohShiny]

The original post mentioned that the analysis was done "at a gem fair using a Sarine DiaMension type system (instead made by OGI Systems)".

I tried to find a Pricescope recommended appraiser but the zip code search did not yield anything in my area. New to the diamond buying/appraising process, please let me know if you have a suggestion on how best to find an unbiased appraiser.

@denverappraiser is an unbiased, PS-recommended appraiser

@oldminer is too.

Both would be excellent choices.

 

[denverappraiser]

Here are some of the large national societies of appraisers that have online member lookups in addition to the list in the menu above.

https://www.najaappraisers.com
https://www.appraisers.org
https://www.ags.org
https://ja-world.com

The vast majority of appraisers out there are associated with jewelry stores but it's usually obvious from their website but, if you can't tell, call them up and ask directly.

 

[Elsa2006]

Thank you for the valuable information.
I appreciate the help.

Here are some of the large national societies of appraisers that have online member lookups in addition to the list in the menu above.

https://www.najaappraisers.com
https://www.appraisers.org
https://www.ags.org
https://ja-world.com

The vast majority of appraisers out there are associated with jewelry stores but it's usually obvious from their website but, if you can't tell, call them up and ask directly.