A good native cut for retaining color ?

[beaujolais]

From Lady Disdain:

I love how sometimes a good native cut is able to maximize colour in a away that precision cut sometimes can''t. ---

I didn''t realize this. Is that because a native cut will be more "flat" (meaning the opposite of brilliant?

Thanks.

 

[morecarats]

A lot of precision cutting is an attempt to import a diamond aesthetic to the colored gemstone world -- that is, the goal is to maximize brilliance.

But if you look at the colored gemstones that get the highest price at auction, you''ll find that most of them are simply but well-cut, with the goal of maximizing color.

Take for example, the 8.2 ct Burmese ruby that Laurence Graff bought for $3.6 million in 2006:

http://www.gemselect.com/other-info/laurence-graff.php

 

[ma re]

The more brilliant the stone, the less saturated the color. That''s why colored diamonds are rarely cut as rounds, since those cuts are the most brilliant and have the best light return. That can, when helped with diamonds extremly high R. I., result in a washed out color, especially in very light tones.

Of course, that might not be as big of a problem with something like a peridot, where color is light but not too much, and R. I. is moderate, so no cut will wash the color out too much. Not to mention that cutters won''t bother deciding on cut so much with common materials, but when it comes to the rare and expensive ones that have a potential of being extremly rich in color like fine rubies or emeralds, it''s a different story. Also, native cuts often are done to preserve as much weight as possible, and at the same time that extra weight in the pavillion (i.e. extra depth) deepens the color, making it seem more rich. Of course, that can become a problem with materials of darker tones like some sapphires, tourmalines, rhodolites etc., but with many stones it''s a good thing.

Native cuts can also preserve weight in the crown, making the pavillion shallow and creating a window, in which case there''s a problem cause color isn''t any richer (but the opposite) and the stone is less brilliant at the same time.

 

[chrono]

I wouldn’t say the result of a native cutting is flat, rather the colour is more concentrated. It may not be as flashy or sparkly as a precision cut stone but the effect is a richer colour.

 

[Sagebrush]

Date: 10/14/2009 2:21:01 AM
Author: ma re
The more brilliant the stone, the less saturated the color. That''s why colored diamonds are rarely cut as rounds, since those cuts are the most brilliant and have the best light return. That can, when helped with diamonds extremely high R. I., result in a washed out color, especially in very light tones.

Interesting statement, but is it true? First of all, "native cut" is simply a pejorative term. Dealers use it to describe sometimes poorly cut stones. The buyer is supposed to believe that the stone was cut by some technologically challenged primitives. I have seen stones perfectly cut on foot treadle powered laps with buffalo horn fittings and by cutters using nothing but their forearms to angle to stone on the wheel. Poor cut is almost always the result of a conscious weight retention strategy.

Color is all about the length of the light path and brilliance is simply total light return. So how does one cancel out the other. I am open to persuasion.

There are times when so-called native cut stones are far superior to so-called precision cuts, if by precision we mean that all excess gem material is removed from the finished stone. Sapphires with bulbous pavilions may contain some extra fat but often these stones will show brilliance (color) at 10-20% from the perpendicular (rock the stone back and forth) where precision cuts will wink out at a 10% angle. Bigger stones may have potentially longer light paths resulting in a gem with a rich body color with richer toned hues refracting from deep within the mysterious heart of the stone.

Remember these natives have been working with and cutting these gems since the Bronze
Age. What do you think, they haven''t learned anything along the way? Who are you calling a primitive, baby?

 

[Barrett]

great post Richard

 

[Harriet]

https://www.pricescope.com/community/threads/native-cut-stones.96917/

 

[Michael_E]

Color is all about the length of the light path and brilliance is simply total light return. So how does one cancel out the other. I am open to persuasion.

They don''t cancel each other, but are inversely related to each other. The shortest light path in a gem is basically two bounces in a stone which is designed to be as short as possible...in and out. Making the path longer by causing more bounces, or making the stone deeper, will make the color deeper. For every increment of increased path length you''ll see a reduction in brightness caused by the absorption of light in that increased path length. It''s called "attenuation" and and it varies between materials depending on the elements which color them and their base elemental makeup. I think of looking into a tall glass of grape juice. Much more light goes through the juice across the glass than through it the long way. The easiest way to see this same effect in gems is to look at pear shapes. They are always deeper in color at their tips, (and much less bright), since the light that leaves from the tip has gone through the stone the long way and usually bounced more than twice.

 

[ma re]

Richard,

I''m not in the business, nor am I cutting stones so I really can''t figure out a proper answer - all I can say is that I read that on one of the (supposed) "specialized sites". Now if only I could remember which one... I think the explanation included something about a high R. I. allowing for a greater speed of light through the material (as opposed to low R. I. stuff), and the increased white light reflections coming from within a stone (that appear more if a stone is more scintillating) fooling the eye into perceiving a lighter shade of color.

 

[mastercutgems]

I think you must take into consideration a well cut native gem or a poorly cut native gem. A native cut gem that has not fallen below critical angle for that gem mineral and does not dump light or makes it where you can read the newspaper through it can be a lively and beautiful gem.

I have re-cut certain gem minerals that were step cut pavilions and brilliant crowns ( which are the main variants in native cuts ) into the western or brilliant cuts and to be honest they did not look as good as the before re-cut. I feel that many "natives" are much better in orienting color and the type of cut a gem needs to give the best color; now when it comes to windows,etc. well I can not see a positive on that cut by any standards as it has a rim of fire on the perimeter and nothing in the center and the eye will focus on the dead zone...

But I have seen some very fine gems that were "native" cut as they did not go against the rules of light and angles for that gem mineral. I will even now sometimes cut gems like that with a step cut all the way to the culet and it does look nice; it is concentrating the eye towards color and not brilliance; but lighter gems I do find respond better to brilliant cuts. It is all in the eyes of the beholder; I guess that is why there are about 5ooo different cut out there; something for every taste... It is like the asscher cut; to me that is like a native cut as you are just step cutting to the culet; you are focusing on color and not brilliance; just like the basic emerald cut; but us cutters do have a tendency to cut what we like and I know I like to see BLING with my color...

But that is just me...

 

[Sagebrush]

Michael,

Interesting, I understand light path. When you say "less bright" does that, in fact wash out the hue or just reduce the saturation? Nice explanation of the tendency of pears, long ovals and marquise to collect more color toward the points. So as mr. Ma Re says, does greater brilliance really reduce the saturation of the hue or the tone, obviously one impacts the other?

Finally a topic with a little meat to it, bravo!

 

[MakingTheGrade]

Very interesting topic! I do think it''s a shame that some people associate "native cut" with "inferior cut", since there are some lovely ones out there.

I have a light blue sapphire that is a well-cut native cut, and I really adore the color and the quality of the color that the native cut gives it. I love that it has dynamic glow rather than a sharp, spiky sparkle.

 

[PrecisionGem]

One of my favorite topics!

I don''t know where the idea came from that a "precision" cutter doesn''t know how to maximize the color of a stone. I think the main difference between a "native" cut, and precision cut is that that the quality of the polish is much higher on a precision cut, the meets of each facet are much more accurate, the symmetry is much better, and typically a "precision" cutter would not cut facets below the critical angle so as to make a stone window. We are not that stupid, in fact we have realized that a deeper pavilion will increase the color of a stone, and we do cut barions all the time for this very purpose. The difference is they are cut well.

Do you really think that if I cut a stone, used a 3000 grit polish instead of 100,000 and cut really quickly so that the meet points didn''t meet, the color would be better?

What the real issue is this, and most of the discussion always surrounds sapphires and rubies.

FACT: Cutters in the US are NEVER going to get a piece of blue sapphire rough that will cut a $10,000 to $100,000 stone. So if you compare a sapphire cut from a "precision" cutter that is selling the stone for $500 to a $10,000 native cut stone, the color will NEVER be as good. Has nothing to do with the cut, it the stone!

FACT: Take 2 pieces of identical lab created ruby material, give one to a "native" cutter, and one to a "precision" cutter. The "precision" cutters stone will be prettier all around.

 

[MakingTheGrade]

Date: 10/14/2009 7:44:38 PM
Author: PrecisionGem
FACT: Take 2 pieces of identical lab created ruby material, give one to a 'native' cutter, and one to a 'precision' cutter. The 'precision' cutters stone will be prettier all around.

You know, I think that'd be a very interesting experiment!

Although it's hard to objectively define or quantify "prettier". Though it would be possible to quantify deepness of color I think as long as you had defined and consistent lighting and angles, etc.

 

[colormyworld]

That is the great thing about these forums in that we can all express our opinions. With that in mind FWIW I am going to disagree with your second "FACT".
The reasom I disagree is because most "presision" cutters will cut out all the fat that RW eludes to above. Not only does that" fat" effectivly minimize the tilt window it also can enrich the color. IMO You know longer light paths and all.

 

[morecarats]

My impression from reading this forum is that many consumers go to precision cutters for colored gems because they want Asscher cuts, even for homely gems like citrine. You''ll rarely find Asschers in so-called native cuts. These consumers value brilliance over color. They want a stone that will sparkle. Basically it''s a kind of diamond envy. It''s a stage you have to go through, like measles or adolescence. Eventually you realize that colored gems are about color. Or you go back to diamonds.

 

[empress]

Exactly, Morecarats -

I love cushion and especially antique cushion cuts. I wonder what a Kashmir Sapphire looks like in a - scissors cut, for example??

I think with colors - it''s the warmth, richness, etc. of the color that we covet.

IMHO

 

[Indylady]

I really don''t think that those who like brilliant gems and asscher cuts do so because they have ''diamond envy'', or that someone who likes brilliance values having brilliance over fine color. I think this may be the case for someone who is looking for a diamond substitute or someone who seeks gem collecting as a means of gaining some sort of social status, but most of the regulars on the colored stones board actually prefer colored stones to diamonds and truly value the color. If I understood what I think you are trying to say, I must argue that it is a vast over generalization.

 

[PrecisionGem]

Date: 10/14/2009 7:58:01 PM
Author: colormyworld
That is the great thing about these forums in that we can all express our opinions. With that in mind FWIW I am going to disagree with your second ''FACT''.

The reasom I disagree is because most ''presision'' cutters will cut out all the fat that RW eludes to above. Not only does that'' fat'' effectivly minimize the tilt window it also can enrich the color. IMO You know longer light paths and all.

I have several cuts that can be tilted more than 20 degrees with no tilt window. It''s not a fat belly that eliminates a tilt window.

Do you think it''s possible for a "precision" cutter to cut the same designs as a native cutter?

Do you think it''s possible for a native cutter to cut the same designs as a precision cutter?

 

[colormyworld]

PG a little extra weight in a belly will help minimize tilt window.

In answer to your first question yes but. IMO most "percision" cutters try to maximize brillance over color.

In answer to #2 My answer is some can.

 

[FrekeChild]

Date: 10/14/2009 9:06:44 PM
Author: szh07
I really don''t think that those who like brilliant gems and asscher cuts do so because they have ''diamond envy'', or that someone who likes brilliance values having brilliance over fine color. I think this may be the case for someone who is looking for a diamond substitute or someone who seeks gem collecting as a means of gaining some sort of social status, but most of the regulars on the colored stones board actually prefer colored stones to diamonds and truly value the color. If I understood what I think you are trying to say, I must argue that it is a vast over generalization.

Ditto. Ditto ditto ditto.

I happen to love precision cut stones. I like sparkle. Do I like diamonds? Not particularly. They are boring. And people who know me at all will tell you that. But if I see something that''s terribly cut, but the color is gorgeous? Color wins every time. I have a stone--probably the next one I''ll set, it''s shallow--.75ct and 6mm. It''s also a teal tourmaline with iridescent inclusions.

I also have another 3 tourmalines that have glorious teal colors and they are terribly cut--so says the precision cutter who sent them to me. But the color...

I don''t see a problem with wanting color AND sparkle.

 

[PrecisionGem]

Date: 10/14/2009 9:35:48 PM
Author: colormyworld
PG a little extra weight in a belly will help minimize tilt window.


In answer to your first question yes but. IMO most ''percision'' cutters try to maximize brillance over color.


In answer to #2 My answer is some can.

Why would a cutter, who is capable of precision cutting and cutting any type of design, knowing that color is the most important thing, not try to maximize color? This really doesn''t make sense. So basically what you are saying is that a native style cutting is better for color, and gives a bigger stone. Stones are sold by weight. A "precision" cutter is able to cut the same style as a native cutter, but chooses not to maximize color and end up with a smaller stone.

A little extra weight in the belly will not minimize a tilt window. A fat belly stone forces the cutter to cut the last few steps in a step cut pavilion below or close to the critical angle. This can be clearly demonstrated with a ray trace program.

 

[colormyworld]

Where did I say that would result in a bigger stone? Perhaps heavier stone would be a more descriptive term. I am actually saying the oppisite. I am willing to forgo a larger face up size to maximize color. Something that most persision cutters act like is a sin. Please do not try and twist my words around

On point 2 I guess we will have to agree to disagree.

 

[PrecisionGem]

sorry, by bigger I meant more weight.

 

[Michael_E]

Date: 10/14/2009 5:31:20 PM
Author: Richard W. Wise
When you say ''less bright'' does that, in fact wash out the hue or just reduce the saturation?

I think that a brighter stone will have a change in both hue and saturation. An overly dark sapphire, for instance, when cut to the brightest angles possible AND to an appropriate size for it''s level of saturation, can be turned into a real head turner as the saturation and hue both become optimal. (Unfortunately this often means a 4mm stone for the really dark pieces). You''ve got to watch it with these stones having dichroism however. I remember cutting one sapphire to what I thought would be a fine looking stone. When I finished it and held to the light it ended up having a nice blue center surrounded by an unattractive green ring. The light was going in at the perimeter of the stone, traversing the entire green axis and coming out without having crossed nearly enough of the blue axis to give it an attractive color.

So as mr. Ma Re says, does greater brilliance really reduce the saturation of the hue or the tone, obviously one impacts the other?

Yes, I think that it does. This is a good thing with darkly colored stones like some sapphire and garnet, which when cut as a deep step cut, just become lifeless and boring. On lighter to medium colored stones though I think that deep crowns and deep pavilions can really bring out the color, particularly if they have a bit of microscopic inclusions to help scatter the light internally...Kasmir sapphire and some very fine rubies being prime examples.

As for precision cutting, I''m all for it. I have no doubt that if an experienced cutter in one of the third world cutting centers was to take the time that I take to cut a stone, (and had adequate laps and polishes), that they could do every bit as good a job as I do. The problem is that, as I read in one of the trade magazines a while back, those "native" cutters are averaging something like 30 stones per day. An impossible job to do and get them all up to par. It''s not a matter of their ability, but of the expectations placed on them.

 

[Michael_E]

Date: 10/14/2009 9:16:51 PM
Author: PrecisionGem

I have several cuts that can be tilted more than 20 degrees with no tilt window.

You know something Gene, I've looked at this from every direction that I can think of and I just don't see this as being possible. In any stone with a flat table and flat facets, having a R.I. under 2 this is hard to believe. Are you thinking of a concave cut stone, apex facets or some other unusual method of doing this. How about some pictures to back this one up ?

 

[movie zombie]

Date: 10/14/2009 8:28:22 PM
Author: morecarats
My impression from reading this forum is that many consumers go to precision cutters for colored gems because they want Asscher cuts, even for homely gems like citrine. You''ll rarely find Asschers in so-called native cuts. These consumers value brilliance over color. They want a stone that will sparkle. Basically it''s a kind of diamond envy. It''s a stage you have to go through, like measles or adolescence. Eventually you realize that colored gems are about color. Or you go back to diamonds.

oh, so well stated!

mz

 

[arjunajane]

Date: 10/15/2009 2:20:01 AM
Author: movie zombie

Date: 10/14/2009 8:28:22 PM

Author: morecarats

My impression from reading this forum is that many consumers go to precision cutters for colored gems because they want Asscher cuts, even for homely gems like citrine. You''ll rarely find Asschers in so-called native cuts. These consumers value brilliance over color. They want a stone that will sparkle. Basically it''s a kind of diamond envy. It''s a stage you have to go through, like measles or adolescence. Eventually you realize that colored gems are about color. Or you go back to diamonds.

oh, so well stated!


mz

Really?
Personally I find more carats'' statement disrespectful and patronizing.
And last time I checked, you do not have to exclude colour in favour of brilliance, or vice versa.
Which is why I choose to use precision cutters, who can achieve both.




I also agree with the core point that we need to differentiate between a poorly cut, windowed etc native cut stone, and a well cut native stone such as the ones Richard describes having seen cut.

I would buy one of these, but not one of the former.

 

[ma re]

Morecarats, I''ve been following your posts, and altough there weren''t many of them, I was pleasantly surprised with the quality of their contents and your views brought up in them - keep up the good work

Others, before you folks engage in a bloody war here

, let me just say that there''s something in both, precision and native cutting, that I appreciate. I like the classic beauty of native cuts, as well as imagination and artistic sense found in precision cuts.

 

[colormyworld]

A jun jane, Isn't it great that we can all share our differing opinions here. Heck in another thread I got to read about how all red spinels are just an overpriced knockoff for possibly irraaition treated rubelite tourmalines!!! Crazy inn't it?