Of Padparadschas and Colour

[chrono]

I’m starting a new thread about colour (hue, saturation, and tone) as not to derail the original thread more than we already did: https://www.pricescope.com/community/threads/do-you-think-this-pad-has-brown-undertones.127615/ In particular, we were discussing the requirements for an orange pink sapphire to be classified as a padparadscha and it is noted that the labs have decided the following definition as quoted by MoreCarats:

Padparadscha sapphire is a variety of corundum from any geographical origin whose color is a subtle mixture of pinkish orange to orangey pink with pastel tones, and low to medium saturation. The name ''padparadscha sapphire'' SHALL NOT be applied in the following cases:
* If the stone has any colour modifier other than pink or orange.
* If the stone has major uneven colour distribution when viewed with the unaided eye and the table up +/- 30 degrees
* If the stone has been treated by lattice diffusion of a foreign element, treated by irradiation or dyed, coated, painted, etc.

We then branched off into the topic of saturation since it is very specific that a strongly saturated orange pink sapphire without any other modifiers with even colour distribution and untreated cannot be called a padparadscha. Perhaps this should be 2 different topics?

Question 1:
Why not include strongly saturated orange pink sapphires as padparadschas? I’ve seen sunsets where the colour is extremely intense and not the pastel associated with padparadschas. Whether these stones are included into that category will not deter any unscrupulous BE (or other treatment). In fact, it is going on at present, despite this classification. I would think that it will be to the benefit of the labs to include these strongly saturated stones, as it increases the quantity of orange pink sapphires to be tested.

Question 2:
What is the colour pink? Should it be a hue onto itself? Can the GIA colour chart be improved by the addition of pink as a stand alone colour? What IS pink? I’ve been taught that pink is a de-saturated red and that any colour that is de-saturated will show brown (if a warm colour) or gray (if a cool colour). However, the derailed discussion made me rethink this as mixing and playing around with paint. I still think that any colour that is de-saturated will show some brown or gray depending on how de-saturated it is. I now think that red really isn’t a de-saturated pink. Here’s why:
Red + white (tone) = pink
Pink + water (de-saturation) = pastel baby pink (most likely with a hint of gray)

 

[T L]

Desaturtion to me means that a stone is devoid of vivid color to some n''th degree. The modifiers that cause a stone to be less vivid are grey and brown. With the paint scenario, I think you have a good analogy there Chrono. If you mix grey or brown, even a smal amount, in a bucket of red paint, the color will get further away from vivid. Although one may not see the grey, it is there because the grey or brown has made the primary color less pronounced. People always tell me that I see grey in stones that they don''t see it in. When a stone is less vivid, therein lies the grey that isn''t obvious, but it''s there.

As far as tonality is concerned, I do think that stones of very dark tones can get desaturated as well since tone is the degree of brightness in a gem. If you add black to the paint in order to increase the tonality, black is akin to very dark grey, and can cause a stone to lose saturation of color while being dark in tone. I''m purposely not a fan of dark or very dark toned stones because I believe very dark tone overlaps with desaturation. Others may disagree of course, but this is my general view on color in gems.

As for padparadschas, my quandry is the fact that the gem labs indicate that these stones should be desaturate (low to medium) in color. What I don''t understand is why one can charge so much for a gem that is desaturate in color. For most transparent colored gems, isn''t saturation of color an important factor in regards to value? I had always thought so, but this seems to fly in the face of that.

Of course this is not to knock anyone''s padparadschas on PS. Everyone has very lovely stones, and they seem more saturate in color than the labs would want for a true padparadscha. It''s almost as if the gem labs are trying to give value to something that is undesirable in a colored gem (desaturation of color). I know that''s a stretch, but it is cause for some of my concern.

 

[LD]

I may be wrong BUT each time this topic has been raised, it''s clear that there is no absolute definition. Some of our resident experts have different ideas to others and sometimes looking at pictures posted, I can see why a gemstone would be classified as a Pad. Other times, a gem just looks pink, or orange but not both. Of course photos are deceptive however I don''t believe there is an "absolute". A similar quandry to when a Sapphire becomes a Ruby etc. Then there''s the discussion about locality? Is it important?

I''d love to see a definitive answer that could be universally applied.

 

[T L]

Date: 10/19/2009 5:26:45 PM
Author: LovingDiamonds
I may be wrong BUT each time this topic has been raised, it''s clear that there is no absolute definition. Some of our resident experts have different ideas to others and sometimes looking at pictures posted, I can see why a gemstone would be classified as a Pad. Other times, a gem just looks pink, or orange but not both. Of course photos are deceptive however I don''t believe there is an ''absolute''. A similar quandry to when a Sapphire becomes a Ruby etc. Then there''s the discussion about locality? Is it important?

I''d love to see a definitive answer that could be universally applied.

Yes, because a premium is charged for a sapphire that is certified by a reputable lab as "padparadscha."

 

[morecarats]

Date: 10/19/2009 5:26:45 PM
Author: LovingDiamonds
I may be wrong BUT each time this topic has been raised, it's clear that there is no absolute definition. Some of our resident experts have different ideas to others and sometimes looking at pictures posted, I can see why a gemstone would be classified as a Pad. Other times, a gem just looks pink, or orange but not both. Of course photos are deceptive however I don't believe there is an 'absolute'. A similar quandry to when a Sapphire becomes a Ruby etc. Then there's the discussion about locality? Is it important?

I'd love to see a definitive answer that could be universally applied.

There HAS been an attempt to give a definitive answer, by the LMHC. Please see the original thread. Chrono quotes relevant parts of the definition at the top of this thread, but doesn't give any information about the source beyond "the labs". You'll find the details in the original thread, including a link to the original document.

The question that a number of people have raised is whether the LMHC did the right thing in specifying that a padparadscha should be of low to medium saturation. I've looked into the history of the LMHC position, and from what I understand, a lot of the scientific work underlying this was done by the AGTA lab in New York. They took a large number of Ceylon padparadscha samples -- stones recognized as fine examples by the trade -- and they did color analysis with photo spectrometers. So there was actually an attempt to scientifically measure the color of padparadscha. Sorry I don't have any detailed information on the measurements, but I will try to find it.

By the way, if you read the LMHC statement quoted by Chrono, you'll see the LMHC is very clear that a padparadscha can come from any geographic location.

 

[chrono]

LD,
Sadly, I agree that there is no absolute definition. However, there should be a clearer guideline and a good reasoning because it affects the asking price the gemstone.

MoreCarats,
Thank you and I’m interested in reading any information or link you have about the study. If that’s the case where many fine orange pink sapphires have been studied, does it mean that natural unheated equally mixed orange pink sapphires do NOT come in strong to intense saturation? That they do not exist, hence only stones with low to medium saturation are considered padparadschas?

 

[morecarats]

Date: 10/20/2009 7:56:01 AM
Author: Chrono

LD,
Sadly, I agree that there is no absolute definition. However, there should be a clearer guideline and a good reasoning because it affects the asking price the gemstone.

MoreCarats,
Thank you and I’m interested in reading any information or link you have about the study. If that’s the case where many fine orange pink sapphires have been studied, does it mean that natural unheated equally mixed orange pink sapphires do NOT come in strong to intense saturation? That they do not exist, hence only stones with low to medium saturation are considered padparadschas?

Sapphires come in almost every color. So there are undoubtedly some unheated orange pink sapphires with highly saturated color.

The best information I have is that the LMHC made a study of recognized cases of padparadscha and drew their conclusions based on those cases. It''s true that the definition is not exact; indeed we don''t really know at this point what counts as low to medium saturation. The LMHC didn''t explicitly address issues of tone, but they imply that only lighter tones would count since they use the term "pastel" in their definition.

The problem here is hardly unique to the definition of "padpardascha". For example, I''ve been grading a lot of blue sapphires this week, trying to decide which stones should be classified as "cornflower blue." There are clear cases of cornflower blue -- what we might call the paradigm cases -- and then there are a lot of borderline cases. The fact that there are borderline cases doesn''t mean that the term "cornflower blue" is meaningless. The LMHC, as I understand it, tried to define the paradigm cases of padparadscha.

At bottom, it''s an issue of language as much as it is gemstones. Take the term "tall". We know that Michael Jordan is tall, and Tom Cruise isn''t. But in a lot of cases we''re not sure whether to label someone as "tall". In my own case, by the time I reached adulthood, I wasn''t a notably tall person. But I got a lot taller after I came to live in Thailand. Maybe it was the food.

I have a few unheated orange pink sapphires that may or may not count as padparadscha. I''m having them tested at AIGS in Bangkok, and I will discuss the testing procedure and the process of deliberation with the lab director there. I''m hoping it may throw some light on the application of the LMHC guidelines in real life. I will be glad to share my findings with the forum.

 

[chrono]

I think your analogy to cornflower blue doesn’t quite fit with the case of padparadscha. Cornflower, to me, is another romanticized name for a specific blue colour because a blue sapphire is a blue sapphire. Its definition is very clear. As with nature, cornflower comes in so many shades of blue that who can say which one is THE cornflower blue that we should base the name on? This is similar to the seafoam green that was discussed last week.

 

[morecarats]

I agree about cornflower blue. I wish customers would stop asking for it. But they read Richard Hughes, so they think they have to have it. Hughes has a lot to answer for ....

 

[chrono]

Perhaps Richard Hughes needs to re-edit his books and commentaries.

In my discussions with him this year, he is of the opinion that one should buy what one likes and not be constrained by what the labs or the market dictates/considers as the most desired colour. This applies in particular to what one considers pink sapphire versus ruby, and green grossular garnet versus tsavorite.

 

[T L]

Date: 10/20/2009 8:40:49 AM
Author: morecarats

Sapphires come in almost every color. So there are undoubtedly some unheated orange pink sapphires with highly saturated color.

The best information I have is that the LMHC made a study of recognized cases of padparadscha and drew their conclusions based on those cases. It''s true that the definition is not exact; indeed we don''t really know at this point what counts as low to medium saturation. The LMHC didn''t explicitly address issues of tone, but they imply that only lighter tones would count since they use the term ''pastel'' in their definition.

The problem here is hardly unique to the definition of ''padpardascha''. For example, I''ve been grading a lot of blue sapphires this week, trying to decide which stones should be classified as ''cornflower blue.'' There are clear cases of cornflower blue -- what we might call the paradigm cases -- and then there are a lot of borderline cases. The fact that there are borderline cases doesn''t mean that the term ''cornflower blue'' is meaningless. The LMHC, as I understand it, tried to define the paradigm cases of padparadscha.

At bottom, it''s an issue of language as much as it is gemstones. Take the term ''tall''. We know that Michael Jordan is tall, and Tom Cruise isn''t. But in a lot of cases we''re not sure whether to label someone as ''tall''. In my own case, by the time I reached adulthood, I wasn''t a notably tall person. But I got a lot taller after I came to live in Thailand. Maybe it was the food.

I have a few unheated orange pink sapphires that may or may not count as padparadscha. I''m having them tested at AIGS in Bangkok, and I will discuss the testing procedure and the process of deliberation with the lab director there. I''m hoping it may throw some light on the application of the LMHC guidelines in real life. I will be glad to share my findings with the forum.

MC,
I, for one, am looking forward to hearing what he has to say. Thank you for doing this.

I agree that the terminology such as grass green, pigeon blood red, cornflower blue, are too vague to properly describe color in a gem.

As for the padparadscha debate, it''s extremely confusing and I would have thought that their definition would be more defined. Is the scientific information behind this definition published anywhere online?

 

[morecarats]

Date: 10/20/2009 9:46:51 AM
Author: Chrono
Perhaps Richard Hughes needs to re-edit his books and commentaries.

In my discussions with him this year, he is of the opinion that one should buy what one likes and not be constrained by what the labs or the market dictates/considers as the most desired colour. This applies in particular to what one considers pink sapphire versus ruby, and green grossular garnet versus tsavorite.

Most labs -- with the notable exception of AGL -- only describe, they don''t prescribe. GIA won''t even give you a clarity grade on your colored stone. If you want prescriptions, you have to read something like "Ruby and Sapphire".

 

[chrono]

Unfortunately, this leaves the consumer in a difficult position. A vendor might call a stone ruby and charge the higher ruby prices, but the stone might be too pink and should be charged a lesser pink sapphire price. The same goes for green grossular garnet and tsavorite. An dishonest vendor might be able to get away with this with a less informed consumer since the labs do not make any distinction yet the trade does.

 

[chrono]

Perhaps this is a stupid question but I’ll throw it out anyway: if the labs will not make the call between a ruby versus pink sapphire, why do they not have the same issue in making the determination as to what a padparadscha is? Why not leave it as an orange pink sapphire? Does it need a separate name when we all know it’s a sapphire?

 

[movie zombie]

Date: 10/20/2009 9:46:51 AM
Author: Chrono
Perhaps Richard Hughes needs to re-edit his books and commentaries.

In my discussions with him this year, he is of the opinion that one should buy what one likes and not be constrained by what the labs or the market dictates/considers as the most desired colour. This applies in particular to what one considers pink sapphire versus ruby, and green grossular garnet versus tsavorite.

is is so very true. those with unlimited $ resources will be able to request and receive the "ideal" but the rest of us will make adjustments. part of getting somewhat educated re some color stones has made me aware that i actually don''t like some of the "ideal" characteristics of particular stones.

mz

 

[Sagebrush]

All,

Very interesting and thoughtful. A few observations that may be useful:

1. Comparing opaque paint chips with transparent media is a procedure fraught with peril. Opaque media cannot achieve the higher saturation of transparent media. (SOTGT)



2. The mixing of paint and the combining of transparent spectral hues yields differing results. So beware of investing too much in that analogy.

3. Hue, saturation and tone are abstractions, they do not exist separately from one another. Color exists.



4. Saturation and tone work together to produce the brightest hue (see gamut limits) (SOGT p.22)



5. I wrote a GemWise blog column on the LMHA and the problem of labs getting into the Connoisseurship business with pads. "Boldly Going Where No Lab Rat Has Gone Before" You may find it of interest.

 

[336336]

I don''t know much about Paps. But I consider it the rich man''s Malaya Garnet

Richard, I love your book!!! I''m a fan

 

[morecarats]

Date: 10/20/2009 10:49:05 AM
Author: Chrono
Perhaps this is a stupid question but I’ll throw it out anyway: if the labs will not make the call between a ruby versus pink sapphire, why do they not have the same issue in making the determination as to what a padparadscha is? Why not leave it as an orange pink sapphire? Does it need a separate name when we all know it’s a sapphire?

Chrono, I don''t which labs you are using, but I have never had a case where a lab has identified a stone simply as "corundum". From the 4 labs I have used this year, reports always come back as "sapphire" or "ruby". Occasionally I will have a case where I send a pink sapphire to a lab to be tested and it comes back as "ruby". I have never had a ruby certified as "pink sapphire," but then we are fairly conservative in what we label ruby.

There are some people who have claimed that the corundum species has 3 members, not 2. Here is an example (from http://www.mineralminers.com/html/corminfo.htm)

"Pure Corundum (Al2O3) is rare in nature and is perfectly colorless. Small amounts of metalic elements can substitute for aluminum in the corundum crystal structure, giving rise to many color variations. Gem corundum of any color is refered to as sapphire with a preceeding color designation if the color is any other than blue. Blue corundum is simply called sapphire. There are two other color varieties of corundum that have specific names, the pinkish-red to red ruby and the orangish-pink padparadscha."

 

[morecarats]

Date: 10/20/2009 10:11:06 AM
Author: Chrono
Unfortunately, this leaves the consumer in a difficult position. A vendor might call a stone ruby and charge the higher ruby prices, but the stone might be too pink and should be charged a lesser pink sapphire price. The same goes for green grossular garnet and tsavorite. An dishonest vendor might be able to get away with this with a less informed consumer since the labs do not make any distinction yet the trade does.

We must be using very different labs. All the reports I receive from AIGS Bangkok, for example, identify tsavorite as "Grossular garnet - Tsavorite". Which labs are identifying chrome green grossular garnet simply as "grossular garnet"? In my experience all the well-known labs use the accepted trade names, such as sapphire, ruby, tsavorite, tanzanite and amethyst. The labs know that is not useful to the consumer to identify a stone as "heated blue zoisite."

 

[chrono]

MoreCarats,
If that’s the case, what is the cut off point between a pink sapphire versus a ruby?
And also, what is the cut off point that makes a stone a tsavorite rather than “just” a green grossular garnet?

The reason I am asking is because not everyone sends their stones to labs for certification; certainly not for smaller stones or something that might not be cost effective. Therefore, I’m curious as to these cut off points that the labs and vendors use. I’ve seen extremely light toned green grossular garnets sold as tsavorites.

 

[morecarats]

Date: 10/21/2009 7:54:49 AM
Author: Chrono
MoreCarats,
If that’s the case, what is the cut off point between a pink sapphire versus a ruby?
And also, what is the cut off point that makes a stone a tsavorite rather than “just” a green grossular garnet?

The reason I am asking is because not everyone sends their stones to labs for certification; certainly not for smaller stones or something that might not be cost effective. Therefore, I’m curious as to these cut off points that the labs and vendors use. I’ve seen extremely light toned green grossular garnets sold as tsavorites.

Chrono, I don''t know the answer, but I will do my best to find out from my lab contacts. My guess is that they use a photo spectrometer that has some arbitrary line (in the case of ruby) between ''more red than pink'' and ''more pink than red''. It would be arbitrary, but could be applied in a consistent way. But this is just my guess.

Do you know some labs which simply refuse to make the distinction between pink sapphire and ruby, as you suggested in your earlier post?

 

[chrono]

I guess my issue isn’t really with the labs but with vendors (other than the padparadschas). The labs obviously have a defined definition although I do not know what it is but does this translate to those in the trade? I doubt most people are going to send their $100 to $1000 red corundrum or green grossular to the labs just to verify that it is a pink sapphire/ruby or green grossular/tsavorite before buying. How does the trade set their prices if there is no defined definition of what is and isn’t a ruby without sending their parcel of stones to the labs? Obviously a stone with the name “ruby” is going to cost more than a pink sapphire so one would think this distinction should be quite clear.

 

[morecarats]

I routinely have inexpensive gems tested. In fact we test samples from every lot of gems we buy, even amethyst. But I realize that the testing is quite a bit less expensive here than it is in the US or (especially) Europe. I think it was AGTA who at one time had a program for low cost identification reports (around $25). But it was apparently a losing proposition, since they couldn''t afford to stay in business.

Generally, a pinkish ruby will sell for less than a true red, though the pink red Burmese rubies are highly regarded. And good quality pink sapphires are actually quite rare, so they command a good price in any case.

 

[ma re]

Chrono mentioned something I wanted to say about TL''s questions - padparadscha is obviously one of those stones similar to grossulars in a sense that both are valued for being as bright as possible without crossing a certain border of being too saturated (in which case a pad becomes a pink or orange sapphire, and a grossular becomes a tsavorite). They should have as strong of a color as possible without becoming too bright, vivid, neon, or anything of that sort.

 

[Sagebrush]

336336,

Thanks for the kind words.

 

[Sagebrush]

336336,

Thanks for the kind words.

 

[morecarats]

I thought I would pass on some information about how one lab (AIGS Bangkok) handles the testing of padparadscha sapphire.

They made it clear that to me that they don''t consider this a scientific identification. But what they do is look for a color mix of orange and pink that is very close to 50:50. They won''t use the term "padparadscha" for pink sapphires with just a touch of orange (or worse, brown), or orange sapphires with just a touch of pink.

They didn''t comment on issues of saturation or tone, just color. I had the sense they don''t consider this issue to be of serious gemological interest.

 

[chrono]

So at least for AIGS, the saturation doesn’t play a strong role in the definition of a padparadscha? So it doesn’t matter that it is pastel or medium toned, low saturation or strong saturation?

 

[morecarats]

In the email I had from AIGS on the topic, they didn''t mention color saturation or tone. But I will follow up with them and ask the question explicitly. I didn''t want to ask them any leading questions in my first inquiry, since I wanted to see what factors they would mention first.

 

[LD]

Date: 10/20/2009 10:38:29 PM
Author: morecarats

Date: 10/20/2009 10:11:06 AM
Author: Chrono
Unfortunately, this leaves the consumer in a difficult position. A vendor might call a stone ruby and charge the higher ruby prices, but the stone might be too pink and should be charged a lesser pink sapphire price. The same goes for green grossular garnet and tsavorite. An dishonest vendor might be able to get away with this with a less informed consumer since the labs do not make any distinction yet the trade does.

We must be using very different labs. All the reports I receive from AIGS Bangkok, for example, identify tsavorite as ''Grossular garnet - Tsavorite''. Which labs are identifying chrome green grossular garnet simply as ''grossular garnet''? In my experience all the well-known labs use the accepted trade names, such as sapphire, ruby, tsavorite, tanzanite and amethyst. The labs know that is not useful to the consumer to identify a stone as ''heated blue zoisite.''

Your comment is interesting because I''ve seen a number of IGI reports where they state Zoisite. Tanzanite isn''t mentioned. I''ll see if I can find an example to post.