===+++what is Average Girdle Diameter (AGD)? how it affect the beauty?

[Legend]

Hello,
I have a friend saying that the "Average Girdle Diameter (AGD) is 8.13 (from measurement 8.11-8.15x5.00). This diamond has a little higher crown which gives it more fires (flashes of rainbow). Diamonds have two ways of "speaking": fire or brightness. I like fire "
given depth 61.5, table 56%

I couldn't contact him back yet, so wonder what range of AGD consider "fire" ?

thanks.

 

[Lorelei]

Date: 4/29/2009 12:18:33 AM
Author:Legend
Hello,
I have a friend saying that the 'Average Girdle Diameter (AGD) is 8.13 (from measurement 8.11-8.15x5.00). This diamond has a little higher crown which gives it more fires (flashes of rainbow). Diamonds have two ways of 'speaking': fire or brightness. I like fire '
given depth 61.5, table 56%

I couldn't contact him back yet, so wonder what range of AGD consider 'fire' ?

thanks.

I hope I am understanding correctly, yes fire is aided by a higher crown angle and also a smaller table can help. Some seek out fiery ideal cut diamonds ( FIC) which typically have a steeper crown angle, pavilion angle of no more than 40.6, and a smallish table. The trade off can be with these that sometimes they can face up a little small for the weight as these diamonds can have increased depth.

The girdle does not have anything to do with fire. Averages are not used for girdle measurements just the minimum and maximum in MM.

 

[stone-cold11]

That is just the diameter of the stone, it has nothing to do with performance, just spread. The diameter tells you nothing about the cut, you need the angles. A heavier stone will probably have a bigger diameter, a smaller shallower cut stone can also have a bigger diameter.

 

[Paul-Antwerp]

The only correct thing that I see in the words of your friend is that he calculates the average of the diameter correctly.

From these measurements, he cannot derive that the stone has a higher or a more shallow crown.

Also, when he says that a higher crown gives more fire, this is incorrect. All other factors being equal, a higher crown might increase the likelihood of the stone showing more fire. If however, the other angles are off and the stone leaks more light through the pavilion, the likelihood of fire decreases. And whether the stone will actually show fire depends highly on the lighting environment. In any case, a stone can be both bright and fiery, one does not rule out the other.

Live long,

 

[Legend]

Thank you all for the info.