Hello All,
According to attached images, please advise
According to attached images, please advise
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- Thread starter hnhn
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DejaWiz
Ideal_Rock
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This one is a rather interesting cut to me, because of the measurements and proportions.
First off, the table is rather large at 60%
The pavilion depth at a massive 44.5% jump out at me, as well.
The 14% crown height is a bit shallow and usually found on 60/60 style cuts.
The crown angle of 34.5° is within the perfect super ideal range.
However, that CA isn't going to play well at all with the very steep 41.6° pavilion angle, and the white areas (light leakage) in the arrows image highlight that occurrence.
First off, the table is rather large at 60%
The pavilion depth at a massive 44.5% jump out at me, as well.
The 14% crown height is a bit shallow and usually found on 60/60 style cuts.
The crown angle of 34.5° is within the perfect super ideal range.
However, that CA isn't going to play well at all with the very steep 41.6° pavilion angle, and the white areas (light leakage) in the arrows image highlight that occurrence.
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Correct in that the 41.6 pavilion angle is a huge red flag however the arrows image is from an h&a viewer so obstruction is white and leakage which has to be pretty bad to show up in this scope is black but black can also be a refection of the lens so its not always clear cut.
In this case however it is leakage under the table that is black so your correct it shows a lot of leakage.
DejaWiz
Ideal_Rock
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Thank you for correcting me and giving me a teaching moment, Karl.
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These are not ASET images as @Karl_K as stated.
ASET images look like this (this is from the Whiteflash site...worth reading). Sometimes they have a white background.
The GIA Excellent cut range is very broad and would include some stones that we (pricescope) would not consider well-cut.
You can use the Pricescope search Engine above to help you find stones that should be well-cut. Enter your parameters here which
is located at the top of the page.
You will get a list of stones that looks like the following image. Pay attention to the HCA score circled in red. You want to stay in
the EX range (not VG). You can click on the HCA "EX" and get more info on that particular stone. This should assist you in finding
well-cut stones. Or, you could let us know the specs you're after and your budget and we can post some stones that are well
cut.
ASET images look like this (this is from the Whiteflash site...worth reading). Sometimes they have a white background.
A Guide to the Angular Spectrum Evaluation Tool (ASET)
The ASET from the AGS is a simple device that quickly provides a wealth of information about how a diamond handles light. Learn how to use it here.
www.whiteflash.com
The GIA Excellent cut range is very broad and would include some stones that we (pricescope) would not consider well-cut.
You can use the Pricescope search Engine above to help you find stones that should be well-cut. Enter your parameters here which
is located at the top of the page.
You will get a list of stones that looks like the following image. Pay attention to the HCA score circled in red. You want to stay in
the EX range (not VG). You can click on the HCA "EX" and get more info on that particular stone. This should assist you in finding
well-cut stones. Or, you could let us know the specs you're after and your budget and we can post some stones that are well
cut.
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That's interesting.
According to GIA's original Cut Estimation Tables those primary proportions should knock it to GIA VG.
Computer modeling also predicts the fundamental proportions to receive GIA VG, according to their 2006 release.
Fun fact, it also verifies @Karl_K 's daredevil use of that H&A image to predict (gasp) leakage. #scandalous
Compulsory CGI disclaimer: This model was generated with averaged facet group data. It assumes perfect optical precision, which the real diamond would not have. It's a non-specific model used to predict general light behavior for the averaged proportions set.
Jumping to 2021: Facetware shows EX, which seems to contradict the estimation tables / info used for software modeling.
If this was a diamond specific system - assessing all 57 facets, diamond by diamond - it might allow for the contradiction, but this is usually simple chart correlation.
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Statistically, more than 60% of round brilliant diamonds graded by GIA earn the Excellent grade. You're in the right place if you want to learn more about this, and be more discerning.
@hnhn the above is great advice, which will help you eliminate known poor performers using our search engine. If you are considering a diamond that's not listed here you can see its HCA score by going to the menu, selecting RESOURCES > HCA and entering the data manually.
FYI: While over 60% of GIA round brilliant diamonds earn Excellent, only around 20% tend to pass HCA scrutiny. If you're looking for a diamond with reliable light behavior it's a useful tool.
https://www.pricescope.com/education/diamond-certification/diamond-ratings#basics-3
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