Spotting light leakage from simple diamond photos?

[Chiswickian]

I was just looking at diamonds on a well know online seller and in the absence of an Ideal/ASET scope image, the 'expert' helped me spot light leakage from a simple online photo of the diamond. The proportions are good (not far off ideal, but still not perfect). They highlighted what they said is light leakage on the table (see photo attached) and also said that the more irregular the arrows are the more likely light leakage. They highlighted both on the image below.

I'm interested in the opinion of other experts here as to whether this is a good way to spot (at least some of the) light leakage from a basic diamond photo, and if so, there are other tell tale signs I should be looking for on the basic photo, particularly if I can't get an Ideal/ASET scope image? Many thanks.

 

[flyingpig]

I do not know who this expert is. But you have been ill-informed.

1. The shape and size of arrows are highly dependent on the tilt and alignment of diamond and camera. You cannot assess the symmetry of the arrows in this photo; the diamond is tilted.
2. The inner circle is called table reflection. This area almost always returns light.
3 . Small black spots (yellow highlight) between the arrows are obstruction (reflection of the camera body), not leakage. This appears/dissapears as you changes the camera distance or viewing distance.

Unless you are highly experienced, it is difficult to spot leakage in a stone with the ideal proportions. MRBs with high color grades are particularly hard.

 

[Chiswickian]

Thanks flyingpig for the feedback. I always "quotation mark" expert when talking with the "diamond experts" from the apparently respected online sellers (no names, but BN and JA) as I'm sure the experts on this forum are infinitely more expert. I'm leaning more every time I read something, but having this forum for unbiased and real expert advice is a real godsend.

Just to help my understanding, what is an MRB and when you say high colour grades, are you referring to colours nearer to colourless?

Many thanks for your advice.

 

[flyingpig]

MRB is Modern Round Brilliant, or simply Round Diamond.
High colour grades mean G, F, E, D in this case.

A

1.92 Carat cushion modified diamond

This cushion modified cut 1.92 carat J color vvs2 clarity has a diamond grading report from GIA

www.jamesallen.com

B

1.02 Carat cushion modified diamond

This cushion modified cut 1.02 carat J color vvs2 clarity has a diamond grading report from GIA

www.jamesallen.com

These two have similar facet patterns and the videos were taken under somewhat similar conditions.
One has significant leakage than the other. Can you tell which one has more leakage?
Leaky facets are glassy, watery, mushy and show yellowish body color.

It is easier to learn and explain with cushions.

 

[OoohShiny]

One possible way to spot leakage without an ASETscope or IdealScope is to place a piece of brightly coloured card behind the stone and then see if any of the colour is visible through the stone.

You would need it in-hand, though.

 

[Chiswickian]

Flyingpig. Thank you for your response. Looking at the 2 videos, I'm thinking it's the 1.02c diamond that has significantly more leakage. To my eyes the facets on the 1.92c diamond do look clearer and more defined, but I could just be telling myself that by the price difference. Am I right?

I have to admit I've only been looking at round diamonds for my fiance's engagement ring, so haven't really familiarised myself with any other diamond shapes.

Many thanks.

 

[Garry H (Cut Nut)]

That diamond has a very slightly shallow pavilion angle - maybe 40.65 and about 35.5 crown angle - slightly steepish. It should be very nice IRL

 

[flyingpig]

Flyingpig. Thank you for your response. Looking at the 2 videos, I'm thinking it's the 1.02c diamond that has significantly more leakage. To my eyes the facets on the 1.92c diamond do look clearer and more defined, but I could just be telling myself that by the price difference. Am I right?

I have to admit I've only been looking at round diamonds for my fiance's engagement ring, so haven't really familiarised myself with any other diamond shapes.

Many thanks.

Actually, it is the 1.92c that has noticeably more leakage. The 1.02c is top quality.
It is not easy. Again, it is more difficult with the rounds. You just need to look at alot of videos and idealscope images.

 

[Chiswickian]

Ah! Okay I got that one wrong, which unfortunately demonstrates my current naivety.

I know you said I should see light leakage in "Leaky facets are glassy, watery, mushy and show yellowish body color", but I struggle to see the difference between these 2 diamonds. Is there a particular part of the diamond (table, edges, etc.) that I should be looking at, or is it just something you can see when looking at the whole diamond once you have enough experience of looking at similar diamonds?

 

[Garry H (Cut Nut)]

the diamond is backlit so the leakage would not be apparent.
But here is an example

 

[Garry H (Cut Nut)]

The ray is entering one of those little Vee shaped leakage areas that is in every well proportioned round diamond.
All that ray is leaving via the pavilion after a few bounces internally.