What do you find is the most confusing about diamond cut?

[kellyfish]

crown an. stuff. I think I''ll have to defer to the experts on this site or similar to pick any future stone.....

 

[strmrdr]

Date: 3/2/2008 5:41:33 AM
Author: arjunajane
no idea how to understand the aset images

ETA: but have decided to go do my homewk and stop being lazy, so js ignore me!

We need too get Wink too do a vid he does a kicken ASET description.

 

[Missrocks]

This question is kind of off subject, but still refers to cut. Eightstars typically don''t score good on GIA cut grade due to painting. Garry mentioned this on a previous thread. I have never seen 8* but have heard rave reviews. I wonder why this type of brilliateering is common on 8*? I can see why it could be undesireable because it is adding extra weight w/o size. But I guess it must not have a huge visible impact?? Is GIA being overly harsh by downgrading because of this in anyone''s opinion? Just curious.

 

[Missrocks]

Date: 3/2/2008 3:44:49 AM
Author: DiaGem

Date: 3/1/2008 10:35:27 PM
Author: Missrocks

Date: 3/1/2008 2:06:50 PM
Author: DiaGem

Date: 3/1/2008 12:58:23 PM
Author: Missrocks
Thanks Strmrdr and Garry for all the info!


One more question...The first time I saw the fatter vs. skinnier the two diamonds being compared had exact angle combo. Same 80 lgf%, 40.8 pavilion, and I can''t remember the crown angle other than both were the same on both, tables were 56 % and 57 %. One diamond was .14 pts bigger in size than the other. The smaller one had fatter arrows and the larger had skinnier, very distinctly different. Is there another reason that causes the arrows to differ?

Differ in size or appearance?

Fatter vs. skinnier

No..., lgf''s are the reason..., assuming we are talking about a standard RB...

The angle of the main crown facets might change the viewing focus on a portion of the pavilion mains (which are the arrows)..., but not significantly enough to the point of making them appear fatter or skinnier...

Maybe my post was confusing. I was on the same page with Strmrdr, who clarified that GIA rounds to nearest 5 for LGF%, so visual difference (of fatter vs. skinnier) could even be seen on two diamonds with same LGF of 80% - because one could be rounded up from 77.51 and other down from 82.49.

 

[diagem]

Date: 3/2/2008 2:41:11 PM
Author: Missrocks

Date: 3/2/2008 3:44:49 AM
Author: DiaGem

Date: 3/1/2008 10:35:27 PM
Author: Missrocks

Date: 3/1/2008 2:06:50 PM
Author: DiaGem

Date: 3/1/2008 12:58:23 PM
Author: Missrocks
Thanks Strmrdr and Garry for all the info!


One more question...The first time I saw the fatter vs. skinnier the two diamonds being compared had exact angle combo. Same 80 lgf%, 40.8 pavilion, and I can''t remember the crown angle other than both were the same on both, tables were 56 % and 57 %. One diamond was .14 pts bigger in size than the other. The smaller one had fatter arrows and the larger had skinnier, very distinctly different. Is there another reason that causes the arrows to differ?

Differ in size or appearance?

Fatter vs. skinnier

No..., lgf''s are the reason..., assuming we are talking about a standard RB...

The angle of the main crown facets might change the viewing focus on a portion of the pavilion mains (which are the arrows)..., but not significantly enough to the point of making them appear fatter or skinnier...

Maybe my post was confusing. I was on the same page with Strmrdr, who clarified that GIA rounds to nearest 5 for LGF%, so visual difference (of fatter vs. skinnier) could even be seen on two diamonds with same LGF of 80% - because one could be rounded up from 77.51 and other down from 82.49.

Not confusing at all..., you just didn''t mention "GIA or any other report" in your original question...

Good point Storm...

..., I guess at AGS this wouldnt be the case...

, now, which is better you think? strict call or loose?

 

[Missrocks]

Date: 3/2/2008 3:25:46 PM
Author: DiaGem

Date: 3/2/2008 2:41:11 PM
Author: Missrocks

Date: 3/2/2008 3:44:49 AM
Author: DiaGem

Date: 3/1/2008 10:35:27 PM
Author: Missrocks

Date: 3/1/2008 2:06:50 PM
Author: DiaGem

Date: 3/1/2008 12:58:23 PM
Author: Missrocks
Thanks Strmrdr and Garry for all the info!


One more question...The first time I saw the fatter vs. skinnier the two diamonds being compared had exact angle combo. Same 80 lgf%, 40.8 pavilion, and I can't remember the crown angle other than both were the same on both, tables were 56 % and 57 %. One diamond was .14 pts bigger in size than the other. The smaller one had fatter arrows and the larger had skinnier, very distinctly different. Is there another reason that causes the arrows to differ?

Differ in size or appearance?

Fatter vs. skinnier

No..., lgf's are the reason..., assuming we are talking about a standard RB...

The angle of the main crown facets might change the viewing focus on a portion of the pavilion mains (which are the arrows)..., but not significantly enough to the point of making them appear fatter or skinnier...

Maybe my post was confusing. I was on the same page with Strmrdr, who clarified that GIA rounds to nearest 5 for LGF%, so visual difference (of fatter vs. skinnier) could even be seen on two diamonds with same LGF of 80% - because one could be rounded up from 77.51 and other down from 82.49.

Not confusing at all..., you just didn't mention 'GIA or any other report' in your original question...

Good point Storm...

..., I guess at AGS this wouldnt be the case...

, now, which is better you think? strict call or loose?

I had never paid too much attention to LGF% before. I guess having discovered the differences in how the rounding is done, I would prefer an AGS report. I had always prefered GIA before, because AGS is known to be a little soft on color grading at times. Of course no lab is perfect.

 

[strmrdr]

Date: 3/2/2008 3:25:46 PM
Author: DiaGem
Not confusing at all..., you just didn't mention 'GIA or any other report' in your original question...

Good point Storm...

..., I guess at AGS this wouldnt be the case...

, now, which is better you think? strict call or loose?

I really think that any grading system is not too be relied on.
I have always said that buying a diamond is like putting a puzzle together.
There is no one answer.
As far as giving me the data I prefer the AGS approach but a full sarin report is better and a full helium report even better yet for the numbers so I shop with vendors that can provide them.
From the right vendor with the right information it really doesn't matter too me if the diamond is graded by AGS or GIA.
If the numbers aren't available then an IS or ASET image can be used but its better too have both the full numbers and the image.
With step cuts clear regular photos and vids are the major pieces of the puzzle the only important numbers are the table, crown height and LxW. (as you found out most scanners are at times totally useless for anything else on them)
With a RB an IS image and the numbers are the major pieces.
On a princess cut an ASET image is the major piece of information.

 

[arjunajane]

Date: 3/2/2008 11:55:52 AM
Author: strmrdr

Date: 3/2/2008 5:41:33 AM
Author: arjunajane
no idea how to understand the aset images

ETA: but have decided to go do my homewk and stop being lazy, so js ignore me!

We need too get Wink too do a vid he does a kicken ASET description.

Hi strm, I think what you''re trying to do is a great idea, and some educational/instructive videos will be invaluable to this forum.
cheers!

 

[strmrdr]

Just when you think your going too have a some spare time! lol
Several things came up so it wont be this weekend for this but hopefully I will get too it late this week.

 

[diagem]

Date: 3/2/2008 6:22:45 PM
Author: strmrdr

Date: 3/2/2008 3:25:46 PM
Author: DiaGem
Not confusing at all..., you just didn''t mention ''GIA or any other report'' in your original question...

Good point Storm...

..., I guess at AGS this wouldnt be the case...

, now, which is better you think? strict call or loose?

I really think that any grading system is not too be relied on.
I have always said that buying a diamond is like putting a puzzle together.
There is no one answer.
As far as giving me the data I prefer the AGS approach but a full sarin report is better and a full helium report even better yet for the numbers so I shop with vendors that can provide them.
From the right vendor with the right information it really doesn''t matter too me if the diamond is graded by AGS or GIA.
If the numbers aren''t available then an IS or ASET image can be used but its better too have both the full numbers and the image.
With step cuts clear regular photos and vids are the major pieces of the puzzle the only important numbers are the table, crown height and LxW. (as you found out most scanners are at times totally useless for anything else on them)
With a RB an IS image and the numbers are the major pieces.
On a princess cut an ASET image is the major piece of information.

At the end..., we are going to go back to the days that illusion was the main issue for Gem purchasing....

 

[strmrdr]

Date: 3/2/2008 2:32:45 PM
Author: Missrocks
This question is kind of off subject, but still refers to cut. Eightstars typically don''t score good on GIA cut grade due to painting. Garry mentioned this on a previous thread. I have never seen 8* but have heard rave reviews. I wonder why this type of brilliateering is common on 8*? I can see why it could be undesireable because it is adding extra weight w/o size. But I guess it must not have a huge visible impact?? Is GIA being overly harsh by downgrading because of this in anyone''s opinion? Just curious.

I have seen a few 8*s and was not impressed.
Painted stones take a hit in the dispersion metric under the AGS system also.
Personally I think the GIA grade of VG they get is about right.
There is a ton of hype surrounding 8* and too my eyes the diamonds don''t live up too it.
They are excellent in candlelight but if your going to judge a diamond in one lighting condition why not go all the way and get an oec.

 

[strmrdr]

Date: 3/3/2008 4:34:47 AM
Author: DiaGem
At the end..., we are going to go back to the days that illusion was the main issue for Gem purchasing....

Well considering the the entire diamond market is based on marketing and illusion it has never left.
But companies that relly on a hype machine too sell the brand are really hurting in todays market, RA and 8* as two examples.
Many of the "new"(haha) cuts that came out of the SOC program tried this and also failed.

 

[Missrocks]

Date: 3/3/2008 8:32:17 AM
Author: strmrdr

Date: 3/2/2008 2:32:45 PM
Author: Missrocks
This question is kind of off subject, but still refers to cut. Eightstars typically don''t score good on GIA cut grade due to painting. Garry mentioned this on a previous thread. I have never seen 8* but have heard rave reviews. I wonder why this type of brilliateering is common on 8*? I can see why it could be undesireable because it is adding extra weight w/o size. But I guess it must not have a huge visible impact?? Is GIA being overly harsh by downgrading because of this in anyone''s opinion? Just curious.

I have seen a few 8*s and was not impressed.
Painted stones take a hit in the dispersion metric under the AGS system also.
Personally I think the GIA grade of VG they get is about right.
There is a ton of hype surrounding 8* and too my eyes the diamonds don''t live up too it.
They are excellent in candlelight but if your going to judge a diamond in one lighting condition why not go all the way and get an oec.

Thanks for the feedback on the subject. The topic of how different cut variations perform in different lighting situations is also very interesting to me. It''s something I had never given much thought too before.

 

[strmrdr]

Date: 3/4/2008 12:04:59 AM
Author: Missrocks

Thanks for the feedback on the subject. The topic of how different cut variations perform in different lighting situations is also very interesting to me. It''s something I had never given much thought too before.

chunky large facets in general perform better in soft light than smaller facets (both real facets and virtual facets have too be taken into account) but the crown height in a round can make a difference also aka fic because of the extended angles they draw light from tend too buck the trend.

 

[Missrocks]

Date: 3/4/2008 12:47:04 AM
Author: strmrdr

Date: 3/4/2008 12:04:59 AM
Author: Missrocks

Thanks for the feedback on the subject. The topic of how different cut variations perform in different lighting situations is also very interesting to me. It''s something I had never given much thought too before.

chunky large facets in general perform better in soft light than smaller facets (both real facets and virtual facets have too be taken into account) but the crown height in a round can make a difference also aka fic because of the extended angles they draw light from tend too buck the trend.

Just random observations I''ve had. My pave'' in my avatar looks superblingy in low lighting. Maybe its cut or just the overall clustered look. My vintage ring w/ three 20pt round brilliants (more like 60/60 stones) has a superbright look in outdoor lighting (not direct sunlight) but does not perform well at all in soft lighting.

 

[strmrdr]

Date: 3/4/2008 1:06:15 AM
Author: Missrocks

Just random observations I''ve had. My pave'' in my avatar looks superblingy in low lighting. Maybe its cut or just the overall clustered look. My vintage ring w/ three 20pt round brilliants (more like 60/60 stones) has a superbright look in outdoor lighting (not direct sunlight) but does not perform well at all in soft lighting.

single cut or full cut melee and what size?

 

[Missrocks]

Date: 3/4/2008 1:16:37 AM
Author: strmrdr

Date: 3/4/2008 1:06:15 AM
Author: Missrocks

Just random observations I''ve had. My pave'' in my avatar looks superblingy in low lighting. Maybe its cut or just the overall clustered look. My vintage ring w/ three 20pt round brilliants (more like 60/60 stones) has a superbright look in outdoor lighting (not direct sunlight) but does not perform well at all in soft lighting.

single cut or full cut melee and what size?

Full cut melee 1.3 to 2.4mm.

I have some single cut melee 2.1mm my vintage ring. I have never seen them give any reaction except white light, hardly any flashes of color.