Concave vs. Traditional Cut

[BWise]

Recently I asked for opnions on recutting my sapphire. (https://www.pricescope.com/community/threads/should-i-send-this-sapphire-for-recut-by-richard-homer.28985/) Many thanks to those of you who shared your advice. Now the stone is on its way to Richard Homer for his assessment.

When talking about concave cutting, some responses I got were like ''if you like that look'' or ''if that is the way you want to go''. I remember the first time when I saw RH''s work (picture only), I was WOWed and speachless. Now I realize that concave faceting is indeed very different. Since I''ve never seen a concave stone in person, can someone tell me what is the big difference compared to a traditional precision cut (the best traditional cut one can possibly get)?

I know it is very hard to tell from still pictures the brilliance produced by either cut. I learned not to expect the asme amount of light reflection from darker toned stones like sapphire as those from diamonds. A good cut sapphire like this one
(http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=10262&item=4998815962&rd=1) sparks well. The question is: how brilliant is a concave gem? Most concave pictures I''ve see are top views. What about angled views? How dark do they look?

 

[MINE!!]

Peronally, I think they are absolutely yummy!!! I know that Wink has a lot of information on his site about the differences with regualr cuts and concave. If you google Concave gems, you can find a lot of other sites that point out the differences in brillancy VS light return. I know that concave cuts do not do as well on darker colors, but they can improve color with a better cut... Good luck...

I just know what I think it beautiful. When I saw stone I was awestruck. It is personal preferance though.

Good luck!

 

[diamondlil]

Well, just to throw another opinion in the mix . . . maybe it''s me, and I''m probably in the minority here, but I''m not a big fan of the concave cut. Maybe it''s because I''ve never seen one in person, but I think it''s because when I see the concave cut, I think of my class ring (1982). That star-like pattern was very popular in the early 80s. I do have an appreciation for beautiful jewelry in general, and I would admire a concave cut on someone else (I''m looking forward to seeing your ring, Mine!

), but I probably would choose a more traditional cut for myself.

DiamondLil

 

[MINE!!]

Date: 5/29/2005 7:31:37 PM
Author: diamondlil
Well, just to throw another opinion in the mix . . . maybe it''s me, and I''m probably in the minority here, but I''m not a big fan of the concave cut. Maybe it''s because I''ve never seen one in person, but I think it''s because when I see the concave cut, I think of my class ring (1982). That star-like pattern was very popular in the early 80s. I do have an appreciation for beautiful jewelry in general, and I would admire a concave cut on someone else (I''m looking forward to seeing your ring, Mine!

), but I probably would choose a more traditional cut for myself.

DiamondLil

HUMPH!!!

 

[strmrdr]

Iv seen both in person and I like both.
If I had a very well cut traditional cut I wouldnt have it concave cut but if I had a badly cut stone and was considering a recut Id strongly consider a concave cut.

It is hard to put into words they each have there own look. I like both.

 

[MJO]

Personally I love concave cutting but most old time jewelers and gem collectors prefer traditional cutting. As in Gemstones themselves the industry as a whole accepts change very slowly. If I was investing in a fine gem I would think hard cutting in concave since it would limit the market to which I could sell it (I have done it anyway). But for personal use I wouldn''t hesitate. I just sent some Homer cut stones to a stone dealer I know that had never seen concave cutting before and now it is one of her favorate styles.

 

[TKC]

By the way, how do actually the color and light return perform in concave cut stones under natural daylight? I am talking about 2-3 carats size stones. I have a very large concave cut amethyst (36 carats), the color and light return is not too bad. But, I think it would have been much WOWer if it were much smaller (like 2-3 carats). I have never seen in person concave cut stones with smaller sizes (2-3 carats). The RH''s work looks good on the pictures. I don''t know how the actual stones look in person. Since the stones'' pictures are taken under controlled lighting condition (at least in his pictures), how do the actual stones look in natural day light? Are they the same (bright and breathtaking color

)? Any input from the people who have purchased from him?

 

[BWise]

Date: 5/29/2005 9:26:49 PM
Author: TKC
By the way, how do actually the color and light return perform in concave cut stones under natural daylight? I am talking about 2-3 carats size stones. I have a very large concave cut amethyst (36 carats), the color and light return is not too bad. But, I think it would have been much WOWer if it were much smaller (like 2-3 carats). I have never seen in person concave cut stones with smaller sizes (2-3 carats). The RH''s work looks good on the pictures. I don''t know how the actual stones look in person. Since the stones'' pictures are taken under controlled lighting condition (at least in his pictures), how do the actual stones look in natural day light? Are they the same (bright and breathtaking color

)? Any input from the people who have purchased from him?

TKC, you have asked the exact questions that prompted me to start this topic. The only thing I want to add is - how about stones around 5ct?

I showed the pictures to my husband last night and he thinks they are interesting gems but a little werid - i.e. he doesn''t care much for it. But he emphasized that it is all personal taste (cleverly excused himself from decision making).

 

[MINE!!]

My stone is about 2.36Cts. It is a spessartite. I was stunned at the way the color emerged from the stone. It was amazing. I was a little unsure, I admit... but when I saw it.. there was no denying the fact that I loved it.

I was eager to see it in natural light and I was not disappointed. I fear that it takes a bit to really impress me.. but when I saw this stone in natural sunlight, I was in awe.. To quote one of the women who saw it.. "My God, it looks like the cutter stole the sunset and put it in your stone" I am a fan and I think I will always be now.

My stone is in my avatar.

 

[BWise]

Date: 5/29/2005 11:26:13 PM
Author: MINE!!
My stone is about 2.36Cts. It is a spessartite. I was stunned at the way the color emerged from the stone. It was amazing. I was a little unsure, I admit... but when I saw it.. there was no denying the fact that I loved it.

I was eager to see it in natural light and I was not disappointed. I fear that it takes a bit to really impress me.. but when I saw this stone in natural sunlight, I was in awe.. To quote one of the women who saw it.. ''My God, it looks like the cutter stole the sunset and put it in your stone'' I am a fan and I think I will always be now.

My stone is in my avatar.

MINE - I love your spessartitie, it is so beautiful that I can only imagine how brilliant it looks like in sunlight.
I have no doubt that concave technique will work wonders on light or warm color stones. My concern is more with the dark color, say medium to dark sapphire. Richard H. told me that his edge for concave cutting was between tone 6 to 7 (sapphire).

Please, anyone who can share some experience on a tone 6 to 7 stone?

 

[MINE!!]

Just for a little lite reading... maybe these will help. Good luck to you... Keep us informed

http://www.winkjones.com/colored/buycolored.php
http://www.winkjones.com/colored/concave.php

 

[Sagebrush]

Hello All,

For the past year, I have been following the many threads that mention concave cutting. In fact, what I read stimulated me to pay particular attention to concave cuts at the last Tucson Gem Show. I also made a point to meet Richard Homer and to purchase a few of his gems. I have been contemplating this cutting style ever since and now that Mine has opened the discussion, I think that the time has come to make a few observations.

Concave faceting seems to work best in light, bright gems. Yellow and orange are hues that reach they’re peak saturation (saturation gamut) at fairly light tones, as they get darker they become less saturated. Orange, for example, as it gets darker it turns brown! Gem varieties that look their best in lighter tones, gems like spessartite and yellow sapphire, in my view, benefit most from cutting in this style.

Gem varieties that reach there optimum saturation at fairly dark tones, e.g. blue sapphire, ruby, are a different matter. I am put off by concave cut fine blue sapphire. The stone lacks depth and mystery, is too homogeneous. I find the concise rows of tiny regimented flashes depressing, it is simply too uniform.

Unfortunately most gems we see are poorly cut. The concave method in the hands of a master like R.H. produces an exceptionally scintillating gemstone but, then so will traditional styles. With the concave method, the facet faces are (effectively) small and the result is a brilliant gem with a great many precisely arranged tiny scintillas of light. But, a colored gemstone is not a diamond so brilliance and scintillation isn''t everything. A long time ago lapidaries recognized that the more facets you added the greater the scintillation but, they also learned that there is a point of diminishing returns, adding more facets means adding smaller and smaller facets which eventually produces an overall fuzzy appearance that reduces scintillation.

Even that awful bugaboo, “extinction” (the dark gray to black areas between the bright sparks of life) has a role to play in the creation of a beautiful gem. Extinction adds dimensionality, it performs a role similar to a contrasting frame on a fine painting, it helps to delineate, to contrast, to focus and fix in our minds what we are seeing. In other words, a little bit of the negative is necessary to provide the contrast necessary to truly appreciate the positive.

Is there such a thing as over doing perfection? Consider the Eight Star “super ideal” diamond cut. Eight Star claims to produce the most brilliant cut and they do. The Eight Star cut performs so well that diamonds cut to these parameters will exhibit an astonishing 98% light return. This is about as close to technical perfection as you can get. The problem is that the Eight Star diamond is so brilliant that it looks like a headlight, it lacks definition, it is one dimensional, its just too damned bright! I have a similar problem with concave cuts. If I look at a row of concave gems, the precise regimented patterns of scintillation remind me of an LED display. If this sort of uniformity is perfection it is a soul-less sort of perfection that I find depressing and not a little bit boring as well.

Cut is the first “C” in the evaluation of colorless diamond because diamond is all about brilliance and sparkle. It’s mostly about QUANTITY. How do we judge the best diamond, by measuring the quantity of scintillation, amount of brilliance and the percentage of dispersion? Its mostly about the numbers, the highest grade is reserved for gems that deliver the maximum amount of these three attributes in combination. I fully expect that one of our diamond experts will jump in to remind me that some of the considerations I mention were also considered in the development of the new GIA diamond cut grading system but let me point out that these subjective quality factors were among the last things considered and, in the final analysis, have the least effect on the cut grade. I wonder, has anyone ever concave faceted a diamond?

Color is the first “C” in the connoisseurship of colored gemstones and the proper cut is the one that delivers the best QUALITY of color. Thus, the connoisseurship of colored gems is all about quality. This has so far defeated and probably will continue to defeat every attempt to come up with a simple uniform grading system for colored gems. They are just so much more complex than diamonds and are not so easily reducible to a set of letters and numbers.

So my advice is the same as I give in my book, forget the verbiage (even mine) and look at the gem. Every piece of gem rough is unique with its own complex set of challenges. A master cutter is an artist who can look into the rough and figure out how to coax it into being the best it can be. There may be a best style for cutting a given gem but there is no single best style of cutting all gemstones.

As for concave cuts gemstones, I’ll keep looking at each gem one by one and probably keep buying (selectively) as well.

 

[MINE!!]

Richard:

Thanks for the information. It is good to hear from an expert on things such as these. I am sure that some gemstones are not as beautiful in concave as others. And there is no doubt that a well cut traditional stone is magnificant as well.


Thanks for expertise~

 

[valeria101]

Date: 5/30/2005 10:11:50 AM
Author: Richard W. Wise


I wonder, has anyone ever concave faceted a diamond?

I've asked the same some time ago and have been told that it is not possible - the tools do not exist yet.

A branded diamond cut ("Cushette") comes close to the looks of concave cut gems - the facet arrangement is pretty close: lots of paralel facets on the pavilion, much like an overly-faceted princess cut), but those are flat facets, not concave.


Anyway, I just wanted to thank you a good laugh about the depressing "LED display" !

Standard shapes ring that bell a bit, but the asymmetric ones with enough contrast between fascicles of facets are something else, I would think... Are these done commercially at all ?

This is what I have in mind:

by Michael Edwards and Mark Gronlund...

 

[Sagebrush]

AnA,

Another question I have about the concave cut has to do with its effect on Crystal. Maybe MJO has an answer as he has had a number of gems recut or Colored Gemstone Nut. The interior of a concave cut gem appears to me to be a bit misty it seems to lack that crystalline punch. Maybe its just that the myriad tiny rectangular scintals obscures the interior?

A little shaky on this but ther is something going on. Have a beautiful concave cut pink sapphire that sits next to an equally beautiful mixed brilliant cut (on the website) and thats the main difference (other than the facet pattern) Perhaps it like a RBC diamond in that respect, hard to see anything other than the brilliance. The concave has superior brilliance the traditional superior depth and transparency.

 

[MJO]

Date: 5/31/2005 7:16:49 AM
Author: Richard W. Wise
AnA,

Another question I have about the concave cut has to do with its effect on Crystal. Maybe MJO has an answer as he has had a number of gems recut or Colored Gemstone Nut. The interior of a concave cut gem appears to me to be a bit misty it seems to lack that crystalline punch. Maybe its just that the myriad tiny rectangular scintals obscures the interior?

A little shaky on this but ther is something going on. Have a beautiful concave cut pink sapphire that sits next to an equally beautiful mixed brilliant cut (on the website) and thats the main difference (other than the facet pattern) Perhaps it like a RBC diamond in that respect, hard to see anything other than the brilliance. The concave has superior brilliance the traditional superior depth and transparency.

Richard,

You are right that people that like the flash of the portuguese round brilliant cut tend to be drawn to concave cutting. To me the concave cut seems to hide inclussions better also since the brilliance draws your attention away from the inclussion. It looks like just another sparkle in the stone. In low lighting is where I beleive concave cutting is best since it makes the stone glow with less light. This is where you can see the crystal of the stone. Since most fine jewelry in my neck of the woods is worn dressing for parties and dinners it is mostly worn indoors. This tends to show off the stones that are concave cut.

 

[coldfusion]

Yingh,

I can tell you that static pictures posted on the internet don''t do any justice to concave cut stones. The closest picture i''ve seen to capturing the light play in these stones are the ''rotating'' pics on Winks''s site.

I have both light (Aqua) and dark colored (Amethyst) concave cuts. I agree with the poster that says it shows up better in lighter colored stones than darker. You can''t really tell the amethyst is concave cut from more than a few feet away. However, you can tell the aqua is concave cut from pretty far away.

You won''t be disappointed with Richard''s work, they''re one of a kinds.
Chris

 

[BWise]

Richard Homer has been so kind that he loaned me one of his concave sapphire so I can see it in person. I received it today.

Honestly, I am not as impressed as I prepared myself to be. It is indeed very beautiful, but it doesn''t give me the scitillation that I expected. And it does look a bit of lack of depth. I think it is probably not for me.

To be fair, the stone has perfect proportion and sits like a piece of art. Maybe it is the color - as many has discovered, concave cut doesn''t show well on darker, well saturated stone.

 

[Colored Gemstone Nut]

My Observations:

I have been out for a while so I am catching up on a couple past threads

Traditional flat faceting has a depth of color which I believe cannot be matched my concave faceting. Traditional flat faceting provides a pure even crisp depth of color. In highly saturated gems, this traditional cutting style seems to accentuate the fluid crystalline features which some of the finest gems possess within their (gamut limits).

I think the larger flatter surfaces provides more of a bold luster of color. When you speak of transparency, I assume you are referring to the observer being able to see through the gem and out the back. Concave faceting breaks this up by creating many smaller uniform windows which are being viewed compared to traditional faceting in which the back surfaces or "windows" are larger.

I believe concave faceting breaks the color up in the sense that the pure blue which might be displayed in traditional flat faceting is now changed by adding many facet patterns which are reflecting & refracting color many times over in a more chaotic manner changing the gems key color or color of the refracted light affecting the brilliance and color of the sparkle. I believe it is true in flat faceting as well as concave faceting that the body color will remain the same. The biggest change is in the face up view.

I believe concave faceting is more advantageous when used in stones which are lighter in tone. I believe stones which are windowed are primitively cut can also benefit from this style. Especially gems which are windowed. I believe concave faceting in affect closes this “window” I believe Tone is one of the more important considerations when looking at concave faceting.

If a stone is too dark it would less likely benefit from Homer's cutting because the light will not be able to get through the stone in order to return the affects of the cutting back to the viewer. Concave faceting doesn't seem to show up as well in the very dark toned stones and better in medium to light toned gems. If the stone is already a little shallow it could benefit from re-cutting. I think stones which are handicapped in a way benefit more from concave faceting. Gems with large windows or those which display an unevenness of color or “color zoning” also benefit more from this style of faceting

When rocking a gem back and forth you might observe flashes of brilliancy trading places with similar areas of extinction (areas with no flash). I believe concave faceting can obscure these areas of extinction.

When I am an the market for a stone which maintains the optimum “gamut limit” I purchase gems which are patterned in a traditional manner. The color of the finest gems remind me of opening a bag of jolly rancher candies. I would love a sapphire which is the equivalent of the jolly rancher lemon or candy apple green.

I opt for a concave faceted stoned when I want a gem which I believe has better dispersion qualities and is lighter in tone. For example a pastel colored sapphire. The play of light is in concave faceting is just as alluring to me as the depth of color traditional faceting provides. I think optimizing a gems qualities through proper cutting is always a challenge. A balance of color and light and how it is viewed through the crown always needs to be optimized when a cutter is custom cutting a gem. I think the big claim about concave faceting is that it provides a more dispersive play of light which traditional faceting lacks.

Both cuts provide beautiful gems. I think coming to terms with accepting this style is harder for some than others because flat faceting is more traditional. I wonder if we would be having this same discussion if concave faceting originated before traditional flat faceting. A big “What If”…..So step out of the “Stone” ages Richard..(Laughing)