scintillation on big vs small stones

[Cehrabehra]

Maybe this is common sense, but I''m seeking confirmation or clarification...

if you have a round ideal with an 85% lgf in both a .5 carat and a 3 carat, you''ll get more frequent scintillation in the smaller stone than in the larger stone, correct? The larger the stone, the broader the flashes, but the less frequent they will be... correct?

 

[strmrdr]

sounds right.

 

[strmrdr]

btw Iv seen a 3ct star129 and it blew my socks off.
the 1ct ones arent that great to my eye they look too busy but at 3ct WOW.

Some of the larger 80+ facet stones are kicken also.

 

[:)]

Threadjack - hey C, new avatar - is that avatar from the pic of your rock''s rainbows on the car?

 

[Cehrabehra]

Date: 9/3/2006 12:07:23 AM
Author: strmrdr
sounds right.

I ask because I was comparing this 2.71 carat to a friend''s .5 carat and hers just seemed to sparkle more... but from end to end when I think about it it didn''t, it just took longer for mine to travel... and hers seemed to all be on the crown where as mine is so big you can look into it and it''s like looking at pictures from space of those nebula where new stars are forming... I just don''t know what is normal.

 

[Cehrabehra]

Date: 9/3/2006 12:12:57 AM
Author: strmrdr
btw Iv seen a 3ct star129 and it blew my socks off.
the 1ct ones arent that great to my eye they look too busy but at 3ct WOW.

Some of the larger 80+ facet stones are kicken also.

yeah I was looking at all of jonathan''s videos today on scint etc. and it got me thinking... and I was reading some old posts of yours storm about lgf''s at 85% etc. and was thinking... if I had a 1 carat stone with 75%lgf (all refering stones here are IRBs) vs a 3 carat stone with 75% lgf... and a 1 carat stone at 85% vs a 3 carat... in the smaller stone I might want it to be a lower % so I can get *some* broadfire... but in the larger stone I might want it to be 85% to get more scint since the larger facets will satisfy the broadfire itch just because the stone is bigger... make sense? or ??

 

[Cehrabehra]

Date: 9/3/2006 12:18:52 AM
Author:
Threadjack - hey C, new avatar - is that avatar from the pic of your rock''s rainbows on the car?

LOL No, this is from a pic I took in candlelight... in a pitch black room with one candle. It''s on page 3 of the photos

 

[Garry H (Cut Nut)]

Date: 9/3/2006 12:01:55 AM
Author:Cehrabehra
Maybe this is common sense, but I''m seeking confirmation or clarification...

if you have a round ideal with an 85% lgf in both a .5 carat and a 3 carat, you''ll get more frequent scintillation in the smaller stone than in the larger stone, correct? The larger the stone, the broader the flashes, but the less frequent they will be... correct?

You will actually see more virtual flashes in the larger stone - because many in the .5ct stone are too small for your eye to resolve - but there are more flashes per square millimeter in the smaller stone.

This comparison is especialy true in a princess cut to round comparison - the princess cut may have less facets but appears to have many more small virtual facets.

But in direct answer to your question - there are the most virtual facets in a 57% table Tolkowsky stone when the lower girdle facets are around 83.2% (upside down plan view) as GIA measures it and 84.5% as Octonus and the commonsense side view shows. But more scintillation does not mena more sparkle per se.

 

[:)]

Date: 9/3/2006 12:23:47 AM
Author: Cehrabehra

Date: 9/3/2006 12:18:52 AM
Author:
Threadjack - hey C, new avatar - is that avatar from the pic of your rock''s rainbows on the car?

LOL No, this is from a pic I took in candlelight... in a pitch black room with one candle. It''s on page 3 of the photos

Darn, I was going to say that is some SERIOUS beauty!

 

[strmrdr]

Date: 9/3/2006 12:23:01 AM
Author: Cehrabehra

Date: 9/3/2006 12:12:57 AM
Author: strmrdr
btw Iv seen a 3ct star129 and it blew my socks off.
the 1ct ones arent that great to my eye they look too busy but at 3ct WOW.

Some of the larger 80+ facet stones are kicken also.

yeah I was looking at all of jonathan's videos today on scint etc. and it got me thinking... and I was reading some old posts of yours storm about lgf's at 85% etc. and was thinking... if I had a 1 carat stone with 75%lgf (all refering stones here are IRBs) vs a 3 carat stone with 75% lgf... and a 1 carat stone at 85% vs a 3 carat... in the smaller stone I might want it to be a lower % so I can get *some* broadfire... but in the larger stone I might want it to be 85% to get more scint since the larger facets will satisfy the broadfire itch just because the stone is bigger... make sense? or ??

wont work,,,,

the c/p angles are far more important....
a bic is far more directional than a fic.
A small bic with a long lgf the small flashes can and will be seen as larger flashes when they are close together.
Take a fic which tends to scatter the return more and it will look like more smaller flashes.

Also short LGF% tend to return light as mostly fire and longer LGF% as more white light so it wont balance there either.

 

[Cehrabehra]

Date: 9/3/2006 12:37:49 AM
Author:

Date: 9/3/2006 12:23:47 AM
Author: Cehrabehra

Date: 9/3/2006 12:18:52 AM
Author:
Threadjack - hey C, new avatar - is that avatar from the pic of your rock''s rainbows on the car?

LOL No, this is from a pic I took in candlelight... in a pitch black room with one candle. It''s on page 3 of the photos

Darn, I was going to say that is some SERIOUS beauty!

why darn? LOL It''s the same stone... I can throw rainbows with it on just about anything... here''s the ones on the car in a pic full size...

you can see the table on the far left, three of the four main big facets throwing, and the ring on the left. This is an unsized picture.

 

[Cehrabehra]

Date: 9/3/2006 12:36:20 AM
Author: Garry H (Cut Nut)

Date: 9/3/2006 12:01:55 AM
Author:Cehrabehra
Maybe this is common sense, but I''m seeking confirmation or clarification...

if you have a round ideal with an 85% lgf in both a .5 carat and a 3 carat, you''ll get more frequent scintillation in the smaller stone than in the larger stone, correct? The larger the stone, the broader the flashes, but the less frequent they will be... correct?

You will actually see more virtual flashes in the larger stone - because many in the .5ct stone are too small for your eye to resolve - but there are more flashes per square millimeter in the smaller stone.

This comparison is especialy true in a princess cut to round comparison - the princess cut may have less facets but appears to have many more small virtual facets.

But in direct answer to your question - there are the most virtual facets in a 57% table Tolkowsky stone when the lower girdle facets are around 83.2% (upside down plan view) as GIA measures it and 84.5% as Octonus and the commonsense side view shows. But more scintillation does not mena more sparkle per se.

scint can be fire or white, correct? So the more facets (virtual or other) the more scint?

I was playing with a friends'' gorgeous 1/2 carat earlier and it was flashing out of the crown really quick but to go from one crown facet to the next in this 2.7 takes a long time... I mean relatively LOL I still got a good flash or two per crown facet but there was time between where I was like okay where''s the next flash where the small stone was just pop pop pop! now, when I looked really close at the two stones *all* I saw in hers were those pops and in mine I had all of this little tiny pinflash deep in the stone *and* the pops that just weren''t as frequent off of the top. I had medium pops inside the stone too that I couldn''t see in hers... but the biggest pops just weren''t as frequent as in hers.

 

[tanuki]

The scintillation issue is why I really like my 91 facet 1.91 carat Solasfera much more than a standard ideal cut RB of about the same size.
I like the look of a 57 facet RB but was used to the liveliness of one just less than a carat in my old ring. The extra facets gave me the best of both worlds.

I would love to see a video from one of you diamond dealers which compares the different cuts side by side, keeping the relative size of the facets approximately the same and increasing the size of the stone as you increase the facets.

For example a 1 carat well cut RB and a 1.6 carat Solasfera and a 2.5 carat Star129 just to compare the scintillation between them.

Every video I see seems to compare stones that are approximately the same size.

 

[Paul-Antwerp]

Date: 9/3/2006 12:36:20 AM
Author: Garry H (Cut Nut)

Date: 9/3/2006 12:01:55 AM
Author:Cehrabehra
Maybe this is common sense, but I''m seeking confirmation or clarification...

if you have a round ideal with an 85% lgf in both a .5 carat and a 3 carat, you''ll get more frequent scintillation in the smaller stone than in the larger stone, correct? The larger the stone, the broader the flashes, but the less frequent they will be... correct?

You will actually see more virtual flashes in the larger stone - because many in the .5ct stone are too small for your eye to resolve - but there are more flashes per square millimeter in the smaller stone.

This comparison is especialy true in a princess cut to round comparison - the princess cut may have less facets but appears to have many more small virtual facets.

But in direct answer to your question - there are the most virtual facets in a 57% table Tolkowsky stone when the lower girdle facets are around 83.2% (upside down plan view) as GIA measures it and 84.5% as Octonus and the commonsense side view shows. But more scintillation does not mena more sparkle per se.

Maybe, we can agree that it is true, but relative to the size of the virtual facets.

We, for instance, prefer princess-cuts to be cut with only 2 chevron-facets, while most cutters will cut 3 or 4 chevrons. According to us, the virtual facets become too small with too many chevrons, and you lose out on scintillation. Only above say 2 Cts, we would consider adding an extra line of facets.

In the same way, cutters of very small rounds claim that it is better to cut these stones in 8-cut (17 facets total) in stead of in brilliant-cut (57 facets), especially for stones under 0.03 Cts.

Live long,

 

[Cehrabehra]

Date: 9/3/2006 9:18:23 AM
Author: Paul-Antwerp
Maybe, we can agree that it is true, but relative to the size of the virtual facets.

We, for instance, prefer princess-cuts to be cut with only 2 chevron-facets, while most cutters will cut 3 or 4 chevrons. According to us, the virtual facets become too small with too many chevrons, and you lose out on scintillation. Only above say 2 Cts, we would consider adding an extra line of facets.

In the same way, cutters of very small rounds claim that it is better to cut these stones in 8-cut (17 facets total) in stead of in brilliant-cut (57 facets), especially for stones under 0.03 Cts.

Live long,

I could totally see that... do you think it would help to essentially cut small stones like OEC? Maybe with modern depth/angles? just a really short lgf?

Interesting on the princess cuts... I have a friend interested in one and I''ve never considered them but I''ll have to pass this info on to her. I always thought the reason why people LIKED princess cuts is because they had so much insanely tiny pinfire. on a 1 carat diamond the difference between two chevs and 4 would be huge I imagine... and I always thoght the reason people liked princesses is because they were so busy withthe little pins. it is a look, it''s fairly homogonous for my taste, but there''s no doubt it''s beautiful.