Diamond Performance

[dhog]

ACA''S are every bit as good or better than a HOF in my opinion without the price tag

we own 5 and will be adding more to our collection at a later date.

at longer viewing distances the ACA''S look better to me as in alot more
bold flash.

I could be wrong but I think certain polishing techniques make
more facets appear as 1 giving it a larger look and a 3D effect.

cattlemens, staples, office depot, winco, super wally worlds, and many
wine tasting rooms have good lights.

good luck with your ACA

the following is my comparison

https://www.pricescope.com/community/threads/aca-vs-hearts-on-fire-side-by-side-comparison.38689/=

 

[bigrock]

Hi Rhino,

Thanks for your contribution. It's always good to hear from different experts.

You have mentioned that it is possible to have diamonds that will exhibit the best of both brilliance and fire. I know that Solasfera achieves triple flush on BrillianceScope but it's not a RB. Here, I am talking about RBs only and I am interested to know whether there is really a set of proportions that give top-notch performance (I mean number 1 here based on a large sample of observers using their eyes alone) under all lighting conditions? Although I know that there are criticism on the BrillianceScope, I am willing to just use this instrument as a reference for now. Is there any RB that achieves triple flushs repeatedly?

As an exercise, I am actually interested to know what parameters of my ACA can be tweaked to give more fire under spotlights based on the information I have posted. John, no offence to you and Whiteflash. As I said before, I truly enjoy my ACA.

. It performs really well under a wide range of lightings. This is purely an academic exercise. I have heard a lot of people mentioning that smaller tables, larger crown angles, etc will give more fire. But how small is small and how large is large. So, I am hoping to use my ACA as a reference to get better understanding. Thank you.

PS: I will definitely check out the video you mentioned. Thank you.

 

[bigrock]

Hi dhog,

Your ACA is one of those that I have checked out earlier on and it''s a New Line ACA. I also vaguely remembered that my ACA looked slightly bigger than a HOF of an equivalent size. It could be due to the ACA giving out more brilliance especially at the edges but I could be wrong.

I will try out your suggestion to do the comparison at a larger viewing distance and see what happens. Btw, your ACA and ring are beautiful.

I envy you for being able to own so many ACAs.

I wish I could do that.

I am hoping that PS''ers who have compared Classic ACA with HOF can contribute to this thread soon.

 

[Rhino]

Hey LittleStar,

Thoughts/comments below.

Date: 7/14/2006 10:51:54 PM
Author: Little Star
Hi Rhino,

Thanks for your contribution. It''s always good to hear from different experts.

It''s a pleasure to serve.

You have mentioned that it is possible to have diamonds that will exhibit the best of both brilliance and fire. I know that Solasfera achieves triple flush on BrillianceScope but it''s not a RB. Here, I am talking about RBs only and I am interested to know whether there is really a set of proportions that give top-notch performance (I mean number 1 here based on a large sample of observers using their eyes alone) under all lighting conditions? Although I know that there are criticism on the BrillianceScope, I am willing to just use this instrument as a reference for now. Is there any RB that achieves triple flushs repeatedly?

You''re correct in the sense that Solasfera''s would not fall into the classification of traditional round brilliants, as in 57 facet types but they are indeed round brilliant cuts. A more appropriate term would be modified round brilliant cut. I know what you mean though. In answer to your question there are no traditional round brilliant cuts that consistently score a triple flush. There are facet constructions (both major and minor) that do consistently score triple very highs. Interestingly these same facet constructs also max out other technologies with regards to light performance such as the Isee2 and also the Imagem. These are the stones that strmrdr often refers to as GOG classics. There''s more to them however than just maxing out technologies, there is other data that fits into this puzzle as well concerning what constitutes them.

In late 2000 early 2001 we were the only website that featured what was purported as the best reflector images as well as stones that had what were seemingly the best BrillianceScope results. We were very busy at that time sending out this very comparison to folks all over the globe. It became a very interesting study for us because we weren''t dictating what consumers should or should not prefer, although at that time when I was new to reflectors I presented on our website the solid red/black reflector image as the *ultimate*. The consumer opinion we received over the course of that time showed me differently as the greater majority of our clients consistently were picking the stones with the higher BrillianceScope results as their preference. In my mind, the debate about which technology corellated with human observation best was answered. This does not mean I discount reflector technologies nor does it mean I extoll the BrillianceScope as the end all be all. Both have their limitations as well as their strengths. Over 6 years I have grown to appreciate the data I get from both technologies as they both communicate to me certain elements about diamond beauty that help us with our clients. In fact it was after the use of both BrillianceScope and FireScope, which prompted me to make modifications and create our own red reflector which in fact explained BrillianceScope results.

As an exercise, I am actually interested to know what parameters of my ACA can be tweaked to give more fire under spotlights based on the information I have posted. John, no offence to you and Whiteflash. As I said before, I truly enjoy my ACA.

. It performs really well under a wide range of lightings. This is purely an academic exercise. I have heard a lot of people mentioning that smaller tables, larger crown angles, etc will give more fire. But how small is small and how large is large. So, I am hoping to use my ACA as a reference to get better understanding. Thank you.

PS: I will definitely check out the video you mentioned. Thank you.

Along with that video you may also want to view the Solasfera video. It makes an excellent case study to answer the question on your mind. Ie... what can be done to maximize fire?

You see ... this can be a tough question and here''s why LittleStar. When viewing a diamond in direct light environments some folks prefer a more contrasty appearance which is given by diamonds of the shorter lower girdle facet length (when combined with ideal angles). As John explained earlier in this thread ... shorter lower girdles contribute to a broader flash. Lower girdle lengths ranging from the low 70''s to around 75% emphasize this feature. If that is what a person prefers then they should not expect a triple very high from the BrillianceScope. One, perhaps 2 very highs at best.

When you lengthen the lower girdles you create more reflections off the pavilion that are redirecting light straight up through the crown. Hence the creation of more pin fire flash. When you lengthen the lower girdles to around 76-80% and the stars around 60%+/- you get a nice balanced mix of both broadfire and pinfire flash. If this is what a person interprets as more fire (and I would fall into this category), that combined with excellent crown/pavilion angles and table size with no painting or digging and you''re talking my type of goodies.

I''ve demonstrated this in the video I told you about so you can see what I''m talking about. Now ... when you lengthen the lower girdles even more, over 80% and upward to 85% the flashes become more splintery in appearance (long narrow flashes) and now the emphasis shifts to longer thinner flashes combined with pinfire flash whereas the shorter lower girdles placed more emphasis on broadfire.

Outside of direct lighting but in diffuse, diamonds with the longer lower girdles are extremely bright stones. Lots of people who have compared them to H&A''s feel they are as bright or even brighter. Yes it causes clefts in the hearts but whose looking at that after the diamond is mounted? I love great optical symmetry but face up appearance is what concerns me more. You can have ideal optical symmetry and the diamond not be a Hearts & Arrows.

As much as I''d like to contribute more here we''re taking off for a 1 week vacation tomorrow morning so I''ll have to catch up then. In the meantime I hope this helps LittleStar.

Kind regards,

 

[Sundial]

Date: 7/14/2006 10:58:41 AM
Author: Little Star
That's interesting, Sundial. I will definitely find another chance to do the comparison.

I have searched the entire forum for ACA vs HOF comparisons. Most people said that their ACAs are comparable to HOFs. My limited investigations show that all such ACAs happen to be New Line ACAs. Do your ACAs belong to the New Line series as well?

I wonder whether HOFs are also cut like Eightstars and New Line ACAs to give edge-to-edge light return although I doubt it. But it does seem strange that all the people who mentioned that their ACAs are comparable to HOFs own New Line ACAs.

I'm afraid I don't know Little Star. Since the ACA stones in my bracelet are small at about 16 points each I have no specs on them other than general color and clarity. They exhibit a lot of fire, but I don't know if the smaller size is a factor.

 

[JohnQuixote]

Date: 7/14/2006 10:51:54 PM
Author: Little Star
Hi Rhino,

Thanks for your contribution. It''s always good to hear from different experts.

You have mentioned that it is possible to have diamonds that will exhibit the best of both brilliance and fire. I know that Solasfera achieves triple flush on BrillianceScope but it''s not a RB. Here, I am talking about RBs only and I am interested to know whether there is really a set of proportions that give top-notch performance (I mean number 1 here based on a large sample of observers using their eyes alone) under all lighting conditions? Although I know that there are criticism on the BrillianceScope, I am willing to just use this instrument as a reference for now. Is there any RB that achieves triple flushs repeatedly?

As an exercise, I am actually interested to know what parameters of my ACA can be tweaked to give more fire under spotlights based on the information I have posted. John, no offence to you and Whiteflash. As I said before, I truly enjoy my ACA.

. It performs really well under a wide range of lightings. This is purely an academic exercise. I have heard a lot of people mentioning that smaller tables, larger crown angles, etc will give more fire. But how small is small and how large is large. So, I am hoping to use my ACA as a reference to get better understanding. Thank you.

PS: I will definitely check out the video you mentioned. Thank you.

LOL. LittleStar, neither I nor WF would ever be offended that you''re seeking to explore different parameters and correlate light performance - an educated customer is our best customer!

I was just posting in another thread about BScope which may interest you (here).

In your case I believe you would find that technology useful; its metric prefers narrow pavilion mains and design best suited to performance in direct lighting. That is why brands like the Radiant Star and the Leo diamond use BScope in their merchandizing efforts.

I''m running out for now but have comments I hope will be helpful to add later. I hope you''re enjoying your weekend.

 

[Cehrabehra]

Date: 7/13/2006 11:25:58 PM
Author: JohnQuixote

Lower Girdles

The distance the lower girdles run from girdle to culet determine how thick, or narrow, the pavilion mains are: Short lower girdles result in wider pavilion mains. Long lower girdles result in narrow pavilion mains. On most commercial round brilliants the lower girdle facet average ranges between 75-85% in height, with the majority at the upper side of this range.

In simple terms, short lower girdles (wide pavilion mains like on the left) enhance performance in indirect/soft lighting conditions. Long lower girdles (narrow pavilion mains like on the right) enhance performance in very bright lighting conditions. Of course, this assumes robust major proportions and good optical symmetry as a prerequisite.

Since you were comparing two very fine H&A diamonds I think we can safely make those assumptions.

Here are simulated pavilion/hearts views for diamonds at 78, 80 and 82% lower girdle height.* This is the view most focused on for ‘A Cut Above,’ as we feel the lower girdle-pavilion main relationships are the single most important factor for light return and visual balance through a broad range of normal lighting conditions. As Brian Gavin says, “It’s all in the hearts.”

Here are crown/arrows views:

John - do you have any examples of lower girdle heights for 50-70%? I haven''t read this whole thread, but just based on your examples, the chunkier is better thing is in my head, based on your above examples. Obviously I imagine too chunky isn''t good... maybe? but Im curious...

 

[bigrock]

Hi Rhino,

Yes, you are correct. I was referring to a 57/58 tranditional round brilliant cut whenever I mentioned RBs. I should have been clearer in my post. Thanks for pointing it out.

I have viewed the two videos you mentioned. Wow, they are so educational. It's a pity I didn't discover them earlier. Now, I truly understand the difference between broad flash and pin flash. I have a vague understanding of what the differences are when I buy my diamond. At that time, I believe I would prefer diamonds that give more pin flashes rather than a few broad flashes. The video makes it clearer to me and confirms that my preference for diamonds with more pin flashes is correct.

During my diamond selection, I have intentionally selected a Classic ACA with a longer LGL. As I am buying it sight unseen, I hope that this combination will give me a diamond that is more in line with my preference. In the Minor Facets section on your web site, you have listed a diamond with 55% stars and 81% lower girdles height which you claimed to be "one of most aesthetically beautiful stones within the H&A diamonds and is usually TEAMING with fire and scintillation". I have attached the IdealScope image of my ACA (52% stars, 79.7% lower girdles height) below for your reference. You would see that the IdealScope image is very similar (in terms of arrow thickness, hotspots, etc) to the DiamXray image for that diamond profiled on your site. Though I have not bought my diamond from you (I don't rule out buying one from you in future

) as I couldn't find anything that fits my budget and preference at that time, your amazingly educational site has assisted me in my diamond selection.

So my question remains. How is it that the HOF I have compared with my ACA has more pin flashes? I know that this could be due to the HOF having longer LGL than my ACA. But I have viewed the hearts image of the HOF and there are no clefts. Since my ACA already has a rather long LGH (79.7%), it seems unlikely that the difference in fire I have seen could be due to the difference in the LGH.

In the "Nature of Scintillation" video, diamonds with comparatively longer LGH are brighter under diffused light and have more pin flashes of fire under spotlight. I have a question for you. What is the maximum LGH possible before this breaks down? Also, there is no mention that diamonds with shorter LGHs will perform better under indirect light. In your opinion, do you think this is true?

Btw, have a great vacation!

I look forward to your replies when you are back.

 

[bigrock]

Hi John,

Thanks for the link, interesting discussion there. I look forward to your further comments.