LGF Depth/Length, Star Facet, and Lower half relationships

[KobiD]

Re: LGF Depth/Length, Star Facet, and Lower half relationshi

Karl, would you mind punching out the same images in plain red and black as your first set were for comparisons sake, please.

IS doesn't show the difference as well as ASET which is why I picked it.

Roger that. But for educational purposes, I think it would be interesting to be able to relate to how it would look in the black/red idealscope as that is what most people request when purchasing a diamond. Understand if you don't want to/are too busy though. We all have lives outside of forums.

 

[KobiD]

Re: LGF Depth/Length, Star Facet, and Lower half relationshi

Also, while the first images woth the 75% lgf depth show some diminshed performance, how would they score on the AGS light performance tests? Is it essentially the same thing. I'm guessing they would still make the 0 score mark, but obviously still have some room for improvement..

..or is it a case that such a stone may actually score better due to some of its lack of symmetry than it otherwise would?

Clearly, the real proof is in the pudding, and that would be to get an IS/ASET of an actual stone of such proportions.

 

[Karl_K]

Re: LGF Depth/Length, Star Facet, and Lower half relationshi

Clearly, the real proof is in the pudding, and that would be to get an IS/ASET of an actual stone of such proportions.

yep
That is my recommendation.

 

[Texas Leaguer]

Re: LGF Depth/Length, Star Facet, and Lower half relationshi

Also, while the first images woth the 75% lgf depth show some diminshed performance, how would they score on the AGS light performance tests? Is it essentially the same thing. I'm guessing they would still make the 0 score mark, but obviously still have some room for improvement..

..or is it a case that such a stone may actually score better due to some of its lack of symmetry than it otherwise would?

Clearly, the real proof is in the pudding, and that would be to get an IS/ASET of an actual stone of such proportions.

Kobi,
I think you are in the realm of making separations related to differences between ideal and "super ideal". To find AGS outliers - stones that squeeked by the ray tracing system into the AGS0 grade but have some LP deficits visible in reflectors - you can browse through the inventories of vendors who deal in high precision diamonds. In addition to their super ideals they will usually have a second category of near misses. It can be instructive to study those diamonds and their numbers and associated LP images to see things that tend to cause a miss. (Unfortunately, it will not help to study GIA stones in this manner for the reasons mentioned earlier - star and lower are rounded to the nearest 5%.)

While doing this exercise be aware that some vendors will drop a stone out of super ideal for reasons other than cut quality. For instance scratches, chips, extra facets, or clarity characteristics that diminish light performance.

 

[Karl_K]

Re: LGF Depth/Length, Star Facet, and Lower half relationshi

I agree with Bryan your at the point where watching videos and comparing numbers to images would be helpful.
The next step after that is ordering an ASET and IS and going to see diamonds live and comparing the numbers to what you see. You can also see how useless the gia numbers are very quickly.
Some stores get a little annoyed when you go browsing and use them others actual enjoy the interaction if it is not busy.
Don't go on busy days or distract the sales people if other customers are there if your just learning.
Be polite and I bet you will find at least one that welcomes you and enjoy the interaction and even wants to try the toys.
More than once I have found jewelery store owners and employees who wanted to view every diamond in the place under the scopes.
You also will find some that blow you off or even ask you to leave.
Be polite and leave if they do so.

 

[KobiD]

Re: LGF Depth/Length, Star Facet, and Lower half relationshi

Thanks for the suggestions. I think I'll try and get my hands on an ASET/IS (or both). Not sure if I'll have the free time to go chasing jewellers around, but they'll definitely be worth owning, and if the opportunity arises I may see if I can browse some inventory. A man can never have too many tools!