Crown/pavilion angle combinations

[Kim N]

A couple of you have noted that 35/40.9 is not a good crown/pavilion angle combination. But what about variations thereof?

For example:

- 34.8/40.9
- 34.9/40.9
- 35/40.8
- 34.8/40.8
- 34.7/40.9
- 34.7/40.8

Are any of the above six combinations good combinations?

Thanks in advance.

 

[JohnQuixote]

JB... If the diamond is well cut I don''t see 40.9/35 as a problem.

 

[Kim N]

Thanks, John. So the other ones I listed wouldn''t be a problem, either?

 

[Mara]

It's not just about the crown and pavilion angle..they do not stand alone. It's the combination of those along with table and depth and some would argue, the lower girdle facets etc.

For me the sweet spot for a diamond is something like 55% table, 60.7% depth, 34.7 crown and 40.7 pav angle. Or similar to that. But that's just my FAVE ... having seen a few stones like that and some more steep and shallow. If I could choose I'd always go for those, but it doesn't mean I'd throw out a 35 and 40.9 but more for earrings probably. I'm also super picky.

Part of this equation is how your EYE responds to the stones and their numbers. Aljdewey has some sweet specs in her e-ring stone and she was looking for matching side stones to do a 3 stone...I think she saw some that were something like 35 and 40.9 or similar and she didn't feel they had the same POP as the stone in her e-ring. I don't recall EXACT specs but she basically kept looking until she found stones that matched her e-ring almost spot on and the combo of all three together is just breathttaking. Now that is splitting hairs but for some people, it's worth it and if they CAN, why not....for others who just want a blingy sparkly stone, they don't CARE about a .1 on an angle. Will one be UGLY vs the other? NO. It's really about what you want and your preference. No one can tell you how to choose.

 

[Demelza]

Ah, the age-old debate about which combos produce the most beautiful stones. I think Mara is absolutely right that it''s very much a matter of preference. Some people can see differences between a 40.6 and a 40.7, others can''t. I think it''s very difficult to make distinctions when you''re looking at numbers alone (as long as the numbers are within a reasonable range). If you trust the vendor, perhaps you can allow him/her to narrow down the choices and show you a couple of different types of stones. My advice would be not to get too hung up on the numbers. That can drive you crazy. Believe me, I know!! Mara talked me down from a couple of ledges when I was obsessing that my diamond had a 40.6 pavilion angle. Look at the IS images and try to relax. The differences people are talking about are very, very slight, and, to some, imperceptible.

 

[strmrdr]

35/40.9 is borderline steep deep.
Can still be a real nice diamond but in my opinion there are better combo''s.
the minor facet cutting would make a bigger difference than the angle differences you listed.

Also it depends on how they are measured helium scans are accurate enough to make very precise predictions.
The low end low cost scanners its much more of a guess.

 

[Garry H (Cut Nut)]

You guys are at it again!!!

See this thread https://www.pricescope.com/community/threads/does-this-crown-pavillion-angle-combo-work.34485/ Jelly Beans

BTW the ideal-scope image that John posted is of a diamond that has some minor facets adjusted to a shallower angle, so it is kinda cheating to show that those proportions do not leak.

 

[Garry H (Cut Nut)]

Date: 10/11/2005 8:46:19 PM
Author: strmrdr
Also it depends on how they are measured helium scans are accurate enough to make very precise predictions.
The low end low cost scanners its much more of a guess.

Point of interest: Helium''s 2 models both costs less than Sarin Diamension''s most accurate model, which needs 3 interchangeable lenses to improve its accuracy.

Helium make a 8.4mm wide and 16.8mm wide maximum stone width models (1:1 and 2:1).

If you scan a 2mm stone with the 2:1 model then obvioulsy the stone only takes up a small part of the feild of view and the scan will not be as accurate as it would using the 1:1 model.

I expect that the 2:1 might still achieve similar accuracy however as the Sarin with its smaller stone lens in place.

The removal and replacement of the Sarin lenses is itself a source of error.

The sad fact is that most Sarin scanners are operated with too large a lens in place because it is time consuming to change to the right sized lens each time. So this makes a bad situation even worse

 

[strmrdr]

Garry for RB's the top end sarin as used by GOG/Jon is good enough for most uses in my opinion.
For asschers and maybe princess cuts it isnt as good.
Iv ran models in diamcalc using both helium and the top end sarin 3d scan data and while there is some differences its not a lot with RB's.
On a scale of one to 10 the helium would be 10 top end sarin a 7 and the low end scanners between a 2 and a -5.
With asschers its no contest the helium scanner is the only acceptable scanner for 3d modeling use.

The ones im talking about are the 5k models from ogi/sarin which are next to useless in predicting diamond behavior.
As Paul is fond of saying often the best diamonds hug the jaged edge and with the low end scanners you cant tell which side of the line they are on.

edit to add more:
If you want to explore azimuth shift and yaw then the helium scanner is the only way to go but at this point the jury is still out on how small amounts of either will affect a diamond performance.

 

[strmrdr]

All the same diamond.
helium is clearly better but the question them becomes is the sarin data far enough off to make it useless?
I dont think it is.

 

[Garry H (Cut Nut)]

Date: 10/11/2005 10:53:22 PM
Author: strmrdr
All the same diamond.
helium is clearly better but the question them becomes is the sarin data far enough off to make it useless?
I dont think it is.

The answer depends on the definition of Useful.

I have found running DiamCalc or Gem Adviser light return and contrast, especially for Princess cuts, can get 5% different results.

This means that using the AGS method - the scan results could possibly make a big difference in the final grade assigned by AGS. This would be especially true for aGS members who have access to do their own grading via the 3D file upload on-line service that is provided only to AGS members.

BTW that is an excellent representation of the accuracy difference Storm.

I presume you did that all by yourself, simply by downloading the GA and the Sarin 3D files directly off GOG?

 

[strmrdr]

Yep I created the image tonight from the sarin data on the website and the helium scan data that was sent to several people to look at.
That diamond was a topic of discussion on another thread.

There is a greater difference between princess measurements on the 2 machines than rounds.
With asschers its not a contest the sarin often adds ghost facets that dont exist on closly angled steps.
That stone with the azimuth shift is likely a worst case example on rounds.

 

[dyemonds2002]

I just went to the HCA for fun and thought of combos one i did was 63 depth 53 table 34 crown and 40.5 pavillion .08 HCA ex ex ex vg Sec one was 60.1 depth 59 table 34 crown 40.5 pavillion .08 HCA ex ex ex vg its really all about the angles isnt it when it comes down to it all

 

[strmrdr]

Date: 10/11/2005 11:59:43 PM
Author: dyemonds2002
I just went to the HCA for fun and thought of combos one i did was 63 depth 53 table 34 crown and 40.5 pavillion .08 HCA ex ex ex vg Sec one was 60.1 depth 59 table 34 crown 40.5 pavillion .08 HCA ex ex ex vg its really all about the angles isnt it when it comes down to it all

The angles are just the begining or first step from there you go to IS or other scope images and/or high resultion 3d scans.

 

[dyemonds2002]

I have another one and this is all in my mind 62 depth 56 table 36 crown 40.3 doesnt look too good .08 ex ex ex vg lol

 

[Daniel B]

Date: 10/11/2005 7:57:03 PM
Author: Mara

For me the sweet spot for a diamond is something like 55% table, 60.7% depth, 34.7 crown and 40.7 pav angle.

~Mara~
Is this the specs on your beloved TIC?

 

[Daniel B]

Date: 10/11/2005 9:49:51 PM
Author: Garry H (Cut Nut)
You guys are at it again!!!

Yes, I know Garry. And i admire yours and everyone elses patience with us new and enthused learners,
I dont think I, and people alike, won't feel comfortable until we get assured 100% perfect specs for the kind of diamonds we want to get. I know, I know, you cant rely on just paper, but it eases our mind, you know? which brings me to a question I had:

Does ANYONE know what are some good specs on a TIC that favors fire, I'm sorry for the redundancy in some of my questions, This will be the last one (on this subject anyway

)

Storm, yes you did point out that a tic with 75-76 LGF would produce more fire, but you did not mention any angles or star %?

 

[Mara]

Daniel...my lovely 1.60c has a 55% table, 60.5% depth (Sarin says 60.7) w/34.9 crown angle and 40.8 pavilion. The funny thing is that my old TIC 1.29c used to have basically the same specs down to crown and pav, but my 1.60c looks SO much better though I couldn't say WHY. So it's hard to say really....each stone has it's own personality. I adore my 1.60 and it will be very hard to give it up, much harder than it was the 1.29!

ETA: Daniel, originally I posted an Excel diamond stone that had a BrillanceScope which showed more fire than white light or scintillation...that would be a TIC that some could say would lean a tiny bit towards more fire.

 

[Mara]

Daniel...also if you really want to know FIC combinations that borderline TIC...you know what you can do? Play around with the HCA for just a few minutes and you will be able to find some combos to look for if that is what you really want.

aka I spent 2 minutes on HCA and came up with this:

61.6-61.9 depth
54 table
35.6 crown angle
40.6 pav angle
HCA: 1.4 FIC: EX EX EX VG

The crown angle may be a little out of an AGS0 range (not 100% sure), but that would be very close to a TIC with a FIC lean. I'm sure you can go from there...good luck!

 

[Daniel B]

~Mara~

How does your 1.60 tic hold up in average flouro lights? Can you still see the fire through the white light?

A side note: My friend has alittle .50, and in college today i couldn't help but notice how the fire was jumping, it was almost 50/50 to white light in the flouro lights-- must have been the cut. then i saw this other gir'ls 1 carat, and it hardly had any white light at all, not to mention no fire.

Thanks for the ups, but I've played with the HCA and came across very similar porportions as you did.
Problem-- I cant find HandA with those specs-- do you suggest i exclude HandA in my search queries and focus on lesser ideal cuts? I'd hate to do that. every crown angle stops at 35 for HandA. Do you think 35 crowns would give me more color than a 34.4-6?

 

[JohnQuixote]

Date: 10/11/2005 8:38:31 PM
Author: Demelza
Ah, the age-old debate about which combos produce the most beautiful stones. I think Mara is absolutely right that it''s very much a matter of preference. Some people can see differences between a 40.6 and a 40.7, others can''t. I think it''s very difficult to make distinctions when you''re looking at numbers alone (as long as the numbers are within a reasonable range). If you trust the vendor, perhaps you can allow him/her to narrow down the choices and show you a couple of different types of stones. My advice would be not to get too hung up on the numbers. That can drive you crazy. Believe me, I know!! Mara talked me down from a couple of ledges when I was obsessing that my diamond had a 40.6 pavilion angle. Look at the IS images and try to relax. The differences people are talking about are very, very slight, and, to some, imperceptible.

I think this is critical information. The differences between tenths on a page can stand out a lot more than they do when you''re looking at 2 diamonds side by side. We can get so into these numbers on PS that the actual differences become exaggerated and frighten people.

 

[Mara]

My 1.60c looks awesome in almost all lighting..which is why I adore it. The only place I don''t LOVE where it looks is in full blazing sunlight, aka out in the park, it looks like chaos in the stone, like it''s on fire inside...too much going on. But I''m sure some people love that look!

 

[Lynn B]

My beautiful AGS-0 2.36 has the following specs: 55/60.5/34.4/40.8 and it amazes me in every lighting situation except spot-on very bright noon-day sun. I''m with Mara - I just don''t love the look, although the other day a co-worker said to me (out on a lunch-time walk) "OMG - look at your diamond right now! It''s BREATHTAKING!" She LOVED the way it looked in the bright sun. So go figure!

On the other hand, my old stone (a beautiful AGS-0 1.53) had these specs: 56/60.7/34.8/40.9 and I liked better in direct sun - although in my office it didn''t seem to do nearly as well as my current stone does.

It can''t be stated enough -- every stone has its own little unique nuances and its own personality. The numbers are important (lord knows!) but the ultimate test has to be your own eyes.

 

[Demelza]

My stone looks its absolute best (now don't laugh) when walking in a forest. My husband and I vacationed in Tofino (on Vancouver Island) where there are lots of trails through the rainforest. My stone was on fire like you wouldn't believe. I couldn't take my eyes off it and my husband kept saying, "Only you would be looking at your diamond on a walk in an exquisite rainforest with the ocean just off in the distance crashing on the rocks." And I kept saying, "Well diamonds are nature too." I don't know how to best describe that kind of lighting (indirect, filtered?), but it's the best!!!

 

[belle]

demelza,
i totally agree with you on the filtered light. you can see such a crisp clean rainbow of colors in filtered light conditions. that is my absolute favorite by far. full on direct sunlight is just too blinding for me, it is my least favorite.

 

[Demelza]

Date: 10/12/2005 3:54:25 PM
Author: JohnQuixote

Date: 10/11/2005 8:38:31 PM

Author: Demelza

Ah, the age-old debate about which combos produce the most beautiful stones. I think Mara is absolutely right that it's very much a matter of preference. Some people can see differences between a 40.6 and a 40.7, others can't. I think it's very difficult to make distinctions when you're looking at numbers alone (as long as the numbers are within a reasonable range). If you trust the vendor, perhaps you can allow him/her to narrow down the choices and show you a couple of different types of stones. My advice would be not to get too hung up on the numbers. That can drive you crazy. Believe me, I know!! Mara talked me down from a couple of ledges when I was obsessing that my diamond had a 40.6 pavilion angle. Look at the IS images and try to relax. The differences people are talking about are very, very slight, and, to some, imperceptible.

I think this is critical information. The differences between tenths on a page can stand out a lot more than they do when you're looking at 2 diamonds side by side. We can get so into these numbers on PS that the actual differences become exaggerated and frighten people.

So true!! When I was working on my upgrade, I compared my current stone to the one I was trading in a bunch of times. They are both ideal cut H&As, but with very different stats. My old stone was a bit deeper and my current stone is a bit more shallow. I tried over and over again to see the differences, but I just couldn't. When I started hearing that the specs on my current stone weren't as "good", I started freaking out. Had my eyes deceived me? Was I missing something major? I still wonder, what would my old stone do in this lighting? Would it look better than my current stone? I don't think any of my anxiety has a basis in reality -- it's just the idea that it's possible to get the perfect stone that will look great in every lighting condition possible. Well, that's an elusive goal because there will always be a diamond out there that someone says is better because it has this or that combination of numbers. I'm not discounting that there are legitimate differences between stones. I'm just saying that when you're dealing with super-elite stones to begin with, the differences are subtle at best.

 

[Lynn B]

OH, I''m with Dem 100% - I love the filtered light, too. Once while we were waiting for a table in a restaurant, we were sitting outside on a patio surrounded by trees, and my diamond was going CRAZY! I swear, everyone around noticed it, too! What a show! It was so gorgeous (every color of the rainbow!) - totally magical and mesmerizing. I was actually disappointed when our pager went off and we had to go inside!

Lynn

 

[Daniel B]

Date: 10/12/2005 5:23:33 PM
Author: Lynn B
I was actually disappointed when our pager went off and we had to go inside!

Lynn

Hehehe, ya. You know, guys like diamonds too (look at any rap star) Im definatly getting some in my wedding band- why be left out??
Lynn, if you dont mind what are your specs on that ring?

 

[Daniel B]

Oh nevermind-- i think you answered that question above

 

[WinkHPD]

LOL! I am loving it that you discovered about filtered light.

During the Spring, Summer, and Fall I always take my clients from my office, into the hall and especially into a dark corner of the hall, then out of doors into the shade beneath a green leaved tree so that they can see the diamond in many lights. Almost all of my clients tell me they love the light show under the tree the best.

Hint to consumers! When you are looking at a diamond, always make sure to look at it under several lighting conditions! I know that most bricks and mortars stores are not going to be wild about you taking a diamond out of the store, but if you ask nicely one of the sales people should be happy to put it in a secure holder and walk out with you. Stop in a dark spot if you can find one in a hallway, go out under a tree, (be careful in direct sunlight, they can actually hurt your eyes if you stare at them too long) and observe the stone under all of the different lighting conditions. A well cut stone should shine and sparkle in all of them, even when there is very little light available they should grab it and make it special!

Wink