Star facets percent info ......

[jelyjelo]

Hi PS experts, Please help me understand the minor faucets cutting of this diamond:

I''ve got Sarin 3D viewer result with angle info of all the facets, but no star facets percent info. So I am having hard time to interpret the result using the minor facets cutting knowledge I''ve learned from GOG''s website. If I list all the info here, would you help me get the star% info please (using Diamcalc may be)?!
2.318 G VS2 Super ideal cut
table: 57.3 57.0 57.2 57.2 -- avg 57
depth: 61.2%
girdle: 1.2% - 1.6%
crown: 34.6 34.7 34.4 34.5 34.4 34.6 34.5 34.7 -- avg 34.5
upper girdle: 44.0 44.3 42.7 42.6 42.2 42.5 42.4 41.8 42.6 42.6 42.4 42.6 42.0 42.4 42.7 42.3
Upper gdl%: 60.4% 59.4% 56.5% 57.7% 58.9% 58.8% 55.8% 58.1%
star: 24.3 25.0 22.8 22.9 22.5 23.1 22.9 23.2
pavillion: 40.8 40.8 40.9 41.0 41.0 40.9 40.8 40.8 -- avg 40.85
lower girdle: 41.8 41.9 42.0 41.9 42.0 42.0 42.1 42.1 42.1 42.0 42.1 42.1 42.0 42.0 42.0 42.0
Lower gdl%: 78.8% 80.3% 79.6% 78.9% 78.4% 79.3% 78.4% 78.9%
Star/Upper Ratio: 58:42 -- what''s this mean?


Your help/info will be highly appreciated!!!

 

[RockDoc]

Date: 4/12/2005 3:15:11 PM
Author:jelyjelo


Hi PS experts, Please help me understand the minor faucets cutting of this diamond:

I've got Sarin 3D viewer result with angle info of all the facets, but no star facets percent info. So I am having hard time to interpret the result using the minor facets cutting knowledge I've learned from GOG's website. If I list all the info here, would you help me get the star% info please (using Diamcalc may be)?!


2.318 G VS2 Super ideal cut
table: 57.3 57.0 57.2 57.2 -- avg 57
depth: 61.2%
girdle: 1.2% - 1.6%
crown: 34.6 34.7 34.4 34.5 34.4 34.6 34.5 34.7 -- avg 34.5
upper girdle: 44.0 44.3 42.7 42.6 42.2 42.5 42.4 41.8 42.6 42.6 42.4 42.6 42.0 42.4 42.7 42.3
Upper gdl%: 60.4% 59.4% 56.5% 57.7% 58.9% 58.8% 55.8% 58.1%
star: 24.3 25.0 22.8 22.9 22.5 23.1 22.9 23.2
pavillion: 40.8 40.8 40.9 41.0 41.0 40.9 40.8 40.8 -- avg 40.85
lower girdle: 41.8 41.9 42.0 41.9 42.0 42.0 42.1 42.1 42.1 42.0 42.1 42.1 42.0 42.0 42.0 42.0
Lower gdl%: 78.8% 80.3% 79.6% 78.9% 78.4% 79.3% 78.4% 78.9%


Star/Upper Ratio: 58:42 -- what's this mean?


Your help/info will be highly appreciated!!!

Dear Jely

There is a listing of the star facets angles in the above report.

I wish I were talented in drawing graphics to comment on this, but I'll attempt to word it as best that I can.

The star to upper girdle ratio is the the measurement of the distance from the center of the flat part of the star facet to the median point of the tip of the two corresponding upper girdle facets are. This distance represents 100% of the measurement. The ratio is how far from the flat part of the star facet ( which makes up a portion of the table facet) is expressed in percentage of the 100% measurement. In the above example it's 58%. This is the percentage of how far the point ( or maybe said as tip) of the star facet is in that measurement. In the above it is a little greater than half way.

How does this affect the appearance? Its sort of stone by stone call. I've seen 45/55's be very nice, but also seen high 50's to 60% stars look well too.

It depends on how well it is aligned for light reflection/refraction to its corresdoning lower girdle / pavilion main facet. As such, how well and its affect on light return has to be made on an individual basis.

I probably could word this better, but I hope you grasp the general answer for you.

However what is missing from this report is the girdle facet minimum and maximum individual facets measurements.

There are three set of these, probably if you go to the MNF page, you'll see them. These measurements specifically address the measurements at the points of the two "halves" ( upper girdle facets ) and the lower girdle points, at the point of the bezel facets ( Crown Main facets) and the pavilion main facets, and the "valley which are the minimum measuirements.
The uniformity of these measurements is important as if their is a lot of variance of the thickness in each "group", then
the preciseness of the entire faceting is affected.


Rockdoc

 

[Garry H (Cut Nut)]

Move on.
This stone has indexed upper girdle facets (you can read Peter yantzers article off the Journal in the front page)

It has UG cheating for weight retention at the expense of edge to edge brilliance

 

[jelyjelo]

Thank you RocDoc, Garry!
While I am digesting the info you have provided (and "move on"), here is the girdle info:

Girdle bels% 3.1 2.9 3.2 3.0 3.1 3.2 3.1 3.1 3.2 3.0 2.9
Girdle hlvs% 3.1 2.6 3.4 2.6 2.7 3.3 3.4 3.3 3.3 3.2 3.2
Girdle min% 1.4 1.2 1.6 1.4 1.2 1.5 1.5 1.5 1.6 1.6 1.5
(Girdle has 16 min) 1.5 1.5 1.5 1.6 1.4 1.4 1.3 1.2

I thought these girdle numbers look good, am I wrong?

I notice couple of upper girdle facets angle is too steep -- 44 and 44.3 but others seems ok, right?.
Also, isn''t UG cutting contribute the least to diamond''s appearance? - according to Jonathan''s minor facet''s cutting tutorial.

Thank you!!!!!!

 

[jelyjelo]

OK Garry, I did my homework - I''ve read Peter Yanzer''s article about "indexed upper girdle facets".
If I understand it correctly, the stone I posted is not index 3 but more like index 2 -- by looking at the girdle% at hlvs and main/bzls (see my above post for girdle% info).
In another word, to make it index 3 stone, the girdle% at main need to be a lot thicker than it is at hlvs.

Do you agree???

 

[Garry H (Cut Nut)]

Date: 4/12/2005 7:21:37 PM
Author: jelyjelo
OK Garry, I did my homework - I''ve read Peter Yanzer''s article about ''indexed upper girdle facets''.
If I understand it correctly, the stone I posted is not index 3 but more like index 2 -- by looking at the girdle% at hlvs and main/bzls (see my above post for girdle% info).
In another word, to make it index 3 stone, the girdle% at main need to be a lot thicker than it is at hlvs.

Do you agree???

No -it is indexed to near 3 and so it will leak at the upper girdles. I call this cheating.
Idexed 2 is normal and 1 is 8* / line aCA style.

 

[niceice]

Date: 4/12/2005 3:54:51 PM
Author: Garry H (Cut Nut)
Move on.
This stone has indexed upper girdle facets (you can read Peter yantzers article off the Journal in the front page)

It has UG cheating for weight retention at the expense of edge to edge brilliance

It''s all well and good to try and make a determination on the beauty of a diamond "by the numbers"... After all, it''s how we conduct our initial sorting process when we''re evaluating the paper sent over by the cutters, but in the end the final determination must be made based upon visual evaluation of the stone. The numbers only tell part of the picture and a hypothetical one at that... This puppy happens to be a diamond that we represented and regardless of your mathematical opinion of the diamond, it is gorgeous. It was evaluated by a respected independent Graduate Gemologist found here on Price Scope who also thought that it was a gorgeous diamond... All of the math is great, let''s face it, we live by it... But nothing beats taking a look at the actual diamond. There will be a lot of changes made in the market as a result of the changes to the AGS cutting scale as there will continue to be advances in cutting technology, but nothing beats a good set of eyes and in this case - three experienced set of eyes... It''s in your hands JelyJelo - what do you think about it?

 

[jelyjelo]

I am keeping it

Ever since I found PScope, I got obsessed with diamond cutting -- it''s facinating! So I want to lean everything about this diamond - especially so, since it''s mine now. I don''t care if the UG has light leakage or even worse news, I just want to
know everything about it -- good or bad.

So thank you Garry for letting me know the "index 3" (although I still think the main girdle% is not thick enough to make it a index 3);

Thank you RockDoc for teaching me about the star/upper ratio (actually maybe the star% in Jonathan''s tutorial is referring to this ratio after all. So I think my stone''s star% is avg 58%

);

Thank you Todd for finding this beautiful baby for me -- again, I want 40% more if you want to buy back the stone

 

[Garry H (Cut Nut)]

I stand corrected.
I should have checked those girdle #''s - the averages for both minor and major girdle thicknesses are both 3.1% which means there is no adjustment or indexing.

The steep upper girdles are obviluos;ly as a result of the long star length, and that does not cause the same deleterious effect.

Sorry.

 

[jelyjelo]

Thank you thank you thank you!!!!!!!!!!

 

[Rhino]

i was asked to respond to this thread with honest, no bs input so here goes.

Firstly ... your main angles ...

34.5 crown
40.85 pavilion
57% table

No red flags here.

Minors (btw I love having all this data to examine as it not only tells me basic light performance but I can even get into the nuances caused by these minor facet measurements)

Stars in the 58% range ARE EXCELLENT when combined with proper lower girdle facet length and can really add noticeably more scintillation (ie. the sparkle factor). A cherry zone which I am particularly fond of is lower girdle length in the 77-79% range.
Lower girdles average out to 79% (and I know this is coming from a Sarin) so this is lower girdle length (not depth). What this means jelyjelo is that you not only have a diamond with excellent brilliance & fire but you can also add the metric of excellent scintillation as well. I''d love to see the B''scope results on this one.
I would take slight issue with Gary''s comments on the upper girdles. Your upper girdles, overall look fine. Yes it would have been nice to see those 2 upper girdles with angles less than 44 degrees but as I say in my tutorial on the subject ... the least important of the minor facet measurements and it''s only on 2 sets of them (not all 8 sets). Your lower girdle and star lengths contribute 100x more to the appearance of the diamond than the upper girdles do.

Most people who ask for information on this forum do not or are not able to provide this amount of information and if you had come on here with just the crown/pavilion/table data everyone would be singing it''s praises (I personally like to know the information on the other 40/57 facets before making a judgment call which is why you rarely see me review a stone with only the basic Sarin data).

If the stone has excellent optical symmetry to boot (and it appears you have a pretty tight stone here according to the min/max specs) then this looks like a keeper in my book.

 

[jelyjelo]

Hurray......!!!!!!!

I couldn''t be happier now - not only I have 3 sets of experienced eyes to confirm the visual beauty of the stone, I also got 3 cutting experts to get the numbers all checked out! Lucky me!!!!!!!!!!!

Thank you everybody for helping me finish my stone''s cutting study -- the next round is starting soon......

 

[strmrdr]

Thanks Jon, niceice, rockdoc and Garry iv been following this thread closely to see if my observations would line up with the experts but didnt feel qualified enough to answer on an allready purchased diamond.
Garry had me scratching my head for a bit but all is well that ends well :}

Thank you for the lessons :}

 

[strmrdr]

Date: 4/12/2005 11:58:32 PM
Author: jelyjelo
Hurray......!!!!!!!


I couldn''t be happier now - not only I have 3 sets of experienced eyes to confirm the visual beauty of the stone, I also got 3 cutting experts to get the numbers all checked out! Lucky me!!!!!!!!!!!

Thank you everybody for helping me finish my stone''s cutting study -- the next round is starting soon......

Congrates on an awesome diamond :}

 

[jelyjelo]

Date: 4/13/2005 12:27

4 AM
Author: strmrdr
Thanks Jon, niceice, rockdoc and Garry iv been following this thread closely to see if my observations would line up with the experts but didnt feel qualified enough to answer on an allready purchased diamond.
Garry had me scratching my head for a bit but all is well that ends well :}

Thank you for the lessons :}

Aha, now I know why you did not answer my question on another thread strmrdr!

Execuse me for being naive, but why can''t people ask for advise after purchasing a stone?! I''ve noticed a few times on PS, when somebody asked questions about purchased stone, everybody tend to steer away from the thread.

Could it be possible the person just want to learn something?
Could it be possible someone just got a stone before he/she found this wonderful and helpful forumn on PS?

Maybe people just don''t want to hurt others by giving them bad news. I can not speak for everybody but i want my doctor
to tell me straight to my face if I have cancer and only have 1 month to live

I do appreciate your kind thoughts tho

 

[Garry H (Cut Nut)]

No one wants to rain on peoples parade.
Once a diamonddddhloving owners, its power and value goes beyond prettiness.

If you have a choice you might prefer to have a beautiful baby, but if an ugly one pops out then you love it to bits, and anyone who says it is ugly has their own problems.

 

[strmrdr]

Pretty much what Garry said.
If its an already bought stone I want to be very sure of my answers because people get real upset.
If im not 100% right about a diamond one of the experts on here will catch and correct it.
There is less chance of the person getting real upset with a stone they are just considering.
I try to be as accurate as I can be at all times when making recommendations but iv been wrong before and will be again.

If im sure of my answer I will usually post my 2c either way but im more cautious with allready purchased stones prefering the experts to handle it.

People can ask any questions they like about any diamond here at any point in the ownership process and someone will usualy have an answer for them.

hope that makes sence :}

 

[JohnQuixote]

Date: 4/13/2005 1:51:24 AM
Author: Garry H (Cut Nut)
No one wants to rain on peoples parade.

Once a diamonddddhloving owners, its power and value goes beyond prettiness.

If you have a choice you might prefer to have a beautiful baby, but if an ugly one pops out then you love it to bits, and anyone who says it is ugly has their own problems.

So true.

Occasionally I''ll meet someone who learns that I specialize in diamonds - and she holds her ring up to me and asks my opinion of the stone that won her heart.

Sometimes all you can say is ''My...what a beautiful baby.''

 

[jelyjelo]

Date: 4/13/2005 11:41:15 PM
Author: JohnQuixote

Date: 4/13/2005 1:51:24 AM
Author: Garry H (Cut Nut)
No one wants to rain on peoples parade.

Once a diamonddddhloving owners, its power and value goes beyond prettiness.

If you have a choice you might prefer to have a beautiful baby, but if an ugly one pops out then you love it to bits, and anyone who says it is ugly has their own problems.

So true.

Occasionally I''ll meet someone who learns that I specialize in diamonds - and she holds her ring up to me and asks my opinion of the stone that won her heart.

Sometimes all you can say is ''My...what a beautiful baby.''

Oh my, I have a big mouth then......

Guess we just need to learn where to draw the line. I personally like a guy who gives me honest opinion even tho the words are hard to take in the beginning.

 

[JohnQuixote]

Date: 4/14/2005 2

5:39 AM
Author: jelyjelo

Oh my, I have a big mouth then......

Guess we just need to learn where to draw the line. I personally like a guy who gives me honest opinion even tho the words are hard to take in the beginning.

Woops. I may have given the wrong impression. I''ll elaborate.

At a party (for instance), meeting someone I don''t know - who is asking merely b/c they heard I might have some knowledge - I''m uncomfortable being critical, especially when the husband is there looking at me with a hint of ''brother don''t do me wrong'' in his eyes

So if I see something that''s not of high quality I focus on the positive aspects. There is beauty in just about everything if you look for it.

The situation I describe does not pertain to my customers, people here or friends/associates - it''s just that occasional person I meet peripherally. That''s why I thought Garry''s comment was a great simile.

 

[Garry H (Cut Nut)]

Sounds like you should all move down under.

We all just tell it like it is and enjoy the punch ups

 

[strmrdr]

Date: 4/14/2005 2

5:39 AM
Author: jelyjelo

Date: 4/13/2005 11:41:15 PM

Author: JohnQuixote

Date: 4/13/2005 1:51:24 AM

Author: Garry H (Cut Nut)

No one wants to rain on peoples parade.


Once a diamonddddhloving owners, its power and value goes beyond prettiness.


If you have a choice you might prefer to have a beautiful baby, but if an ugly one pops out then you love it to bits, and anyone who says it is ugly has their own problems.

So true.


Occasionally I''ll meet someone who learns that I specialize in diamonds - and she holds her ring up to me and asks my opinion of the stone that won her heart.


Sometimes all you can say is ''My...what a beautiful baby.''

Oh my, I have a big mouth then......

Guess we just need to learn where to draw the line. I personally like a guy who gives me honest opinion even tho the words are hard to take in the beginning.

If im sure of the answer then well its usualy if you dont want to know the answer dont ask.
In this case everything looked good but I didnt feel sure enough on a stone someone allready owned.
Diamcalc is real nice for this kind of question.
Punch in the numbers and it will tell you all about the diamond.
I cant afford a copy right now so dont have it.

 

[jelyjelo]

Don''t worry guys, no "wrong impression" of any sort. I totally understand!
I just want to make sure people still get advise they are seeking for on PS even with the stone in their hand.
I know you guys are just being nice/considerate, no "dishonest" intention at all! so relax, my bad