Kozibe

[Cehrabehra]

Okay I want to talk about kozibe!

When some of us girls were ooohing and aaahhhing over some of the OMCs BECAUSE we loved how the culet was reflected in the crown facets... and I even wanted mine to show the culet in a total face up position... now to hear it is a "bad" thing? Why!!?? can you people plez ''splain to me?

http://www.octonus.com/oct/products/3dcalc/standard/param16.phtml

(from link

What is kozibe ?


"Kozibe" is name of optical effect like "Nail Head", "Fish Eye" and etc.

The term "Kozibe" had been introduced by HRD staff in Antwerp. Kozibe diamonds that show culet through crown main facets in the face-up position. In particular this phenomenon led to strong fading of crown brightness for not very big stones.

This effect is appeared only in diamonds with extra total height (big height is because of either high crown or thick girdle), and that is why it can be used as secondary negative attribute for big stones also.

The value of angle in the field "Kozibe" in the DiamCalc means angle of tilt when observer can see culet through crown facets.

If the value of angle is negative then it is no need to tilt because culet should be seen through all facets of crown.


Now my stone it is very difficult to see the culet and I thought that was a bad thing, but it''s a good thing? and in the yellow part above it says in "not very big" stones - what is not very big? and how does kozibe affect larger stones (what is the cut off between big and not very big - and garry don''t say 6 carats!!!) lol

 

[Garry H (Cut Nut)]

I am not aware of any great contribution from HRD in the world of cut quality and grading.

Kozibie is a feature that in my mind can provide a benefit.
The only time it can make reduced beauty in the crown facets is with very small stones - say under 0.25ct at a guess.

Here are some very attractive proportions for a stone that would have Kozibie of more than 5 degree''s C.

 

[Cehrabehra]

Date: 10/16/2006 4:07:47 PM
Author: Garry H (Cut Nut)
I am not aware of any great contribution from HRD in the world of cut quality and grading.

Kozibie is a feature that in my mind can provide a benefit.
The only time it can make reduced beauty in the crown facets is with very small stones - say under 0.25ct at a guess.

Here are some very attractive proportions for a stone that would have Kozibie of more than 5 degree''s C.

you call this 50 table, 37 crown angle and <40 pav angle "very attractive proportions" for a stone with kozibie?

I don''t imagine this stone would do well on HCA - but in words, what sort of performance expectation, aside from the kozobie, would you expect from a RB with proportions like this?

And in your mind, what benefit can this feature provide?

 

[Garry H (Cut Nut)]

Date: 10/16/2006 7:35:53 PM
Author: Cehrabehra
you call this 50 table, 37 crown angle and <40 pav angle ''very attractive proportions'' for a stone with kozibie?

I don''t imagine this stone would do well on HCA - but in words, what sort of performance expectation, aside from the kozobie, would you expect from a RB with proportions like this?

And in your mind, what benefit can this feature provide?

Cehra a stone like this in plus 1ct will have noticably heaps more fire and scintillation, and will be slightly less bright than what you have been accustomed to in Tolkowsky proportions - but still way brighter than any princess cut ever produced.

For a fire freak - I think you would fall in love with it. Smaller and 3 times more frequent flashes than your old cut - but full of character. A fire whisperer

 

[:)]

Date: 10/17/2006 3:04:57 AM
Author: Garry H (Cut Nut)

Date: 10/16/2006 7:35:53 PM
Author: Cehrabehra
you call this 50 table, 37 crown angle and <40 pav angle ''very attractive proportions'' for a stone with kozibie?

I don''t imagine this stone would do well on HCA - but in words, what sort of performance expectation, aside from the kozobie, would you expect from a RB with proportions like this?

And in your mind, what benefit can this feature provide?

Cehra a stone like this in plus 1ct will have noticably heaps more fire and scintillation, and will be slightly less bright than what you have been accustomed to in Tolkowsky proportions - but still way brighter than any princess cut ever produced.

For a fire freak - I think you would fall in love with it. Smaller and 3 times more frequent flashes than your old cut - but full of character. A fire whisperer

Snort! Choking on soda, laughing so hard!