Colour zoning blue sapphires

[Beautiful-disaster]

Hi there,
In a quest to understand Sapphires (and my own while I wait to get it into the gem lab) I’m wondering if anyone can tell me what I’m looking at here when the sapphires turn clear. I assume it’s colour zoning but am failing to understand it - as these are Kashmir sapphires and seem to all have it. My sapphire does this as well... from directly on it’s blue but from side on it can appear almost clear ?
I thought this was a bad thing as everything I have read about colour zoning is bad. The examples are usually dark sapphires which don’t help me. Mine is very similar to these pics below.
I will post pics of mine in a post underneath (even though I’m terrible at getting good shots of it no matter how I try).

ps I feel bad asking about this as I feel this is something experts know due to their experience but appreciate any help you can offer a layman.
PPS I’m also looking to buy digital calipers and a sonic cleaner if anyone knows where I may purchase these things that isn’t too expensive but also aren’t crappy quality. Is this one of those *you get what you pay for* things?

 

[Beautiful-disaster]

Mine - it’s roughly 8.3cts by weight.

 

[Bron357]

The reason why sapphires are blue or pink or green or yellow is because of the trace elements present while the crystal is developing. colourless sapphire occurs when there are no other trace elements present for whatever reason.
so colour zoning in sapphires is common.
sapphires are also dichroic, this means the crystal is a different colour depending on which axis is being viewed.
For all these reasons, cutters will orientate the sapphire to get the best colour when “face up”. That the direction that you see when looking down in the gem.
if the colour zoning is kept in the horizontal plane, when viewing the sapphire face up you won’t see / notice the colourless zones of the sapphire. This is a reason why some sapphires are “bottom heavy” it’s to help promote the intensity of colour and maintain carat weight. Sometimes cutters have to choose between size and clarity and colour for the “result”.
Sapphires contain rutile inclusions or “silk” when this is excessive it can make the sapphire cloudy so that’s why sapphires are heat treated. It breaks up the silk and makes the sapphire more transparent..
Kashmir sapphires are known for their extremely fine silk that causes the famous “glow” but as with all things, too much silk can cause cloudiness. With a Kashmir sapphire it’s unheated status is very important to its value so often it remains unheated despite its cloudiness.

 

[Beautiful-disaster]

The reason why sapphires are blue or pink or green or yellow is because of the trace elements present while the crystal is developing. colourless sapphire occurs when there are no other trace elements present for whatever reason.
so colour zoning in sapphires is common.
sapphires are also dichroic, this means the crystal is a different colour depending on which axis is being viewed.
For all these reasons, cutters will orientate the sapphire to get the best colour when “face up”. That the direction that you see when looking down in the gem.
if the colour zoning is kept in the horizontal plane, when viewing the sapphire face up you won’t see / notice the colourless zones of the sapphire. This is a reason why some sapphires are “bottom heavy” it’s to help promote the intensity of colour and maintain carat weight. Sometimes cutters have to choose between size and clarity and colour for the “result”.
Sapphires contain rutile inclusions or “silk” when this is excessive it can make the sapphire cloudy so that’s why sapphires are heat treated. It breaks up the silk and makes the sapphire more transparent..
Kashmir sapphires are known for their extremely fine silk that causes the famous “glow” but as with all things, too much silk can cause cloudiness. With a Kashmir sapphire it’s unheated status is very important to its value so often it remains unheated despite its cloudiness.

Thankyou for this!!
I think the term I was missing was *dichroic*.
I did come across some cutting information that really helped to understand.
I really appreciate your time (and patience). You gave me exactly what I needed to know!

 

[LightBright]

Thanks for this fascinating discussion. Super cool!

Bron, is there any thing to look for that distinguishes Kashmir sapphires from others? are they typically dichroic with large portions of Kashmir stones being clear not color? Do other sapphire types (regions) display similar stratification of clear/milky then intensely colored in straight layers of bands? Just curious.

 

[Beautiful-disaster]

Thanks for this fascinating discussion. Super cool!

Bron, is there any thing to look for that distinguishes Kashmir sapphires from others? are they typically dichroic with large portions of Kashmir stones being clear not color? Do other sapphire types (regions) display similar stratification of clear/milky then intensely colored in straight layers of bands? Just curious.

Yes - please - everything Lightbright said.
I found this to be helpful for me to see how/why they are cut the way the are.

 

[Bron357]

Determining origin of gemstones can be relatively simple if there are certain inclusions that are only found at “x” location. Other times a detailed chemical analysis reveals trace elements again attributable to a particular location. Paraiba Tourmalines are an example, when copper bearing they are usually attributed to a Brazilian origin. Without the copper they can’t be called Paraiba. Paraiba tourmaline can be blue or green or even red, it’s the presence of copper that determines that moniker.
Kashmir sapphires are known to contain a microscopic type of inclusion that reflects light to create a unique glow. There are also inclusions of other crystals that can be attributed to Kashmir and some Burmese sapphires.
Again Kashmir is an origin but it does get used as a descriptive “hue /tone”. Not all Kashmir sapphires are the beautiful glowing blue and not all beautiful glowing blue sapphires are Kashmir!
So origin can and does matter but usually it is the quality and desirability of the hue/tone that drives the value. That and an unheated status. Unheated status is important because it follows that the hue/tone is entirely natural. Such sapphires are rare = valuable.
Otherwise everyone would be happy buying perfect colour / hue/ tone lab grown sapphires.

 

[Bron357]

Any sapphire can show colour banding, it’s just how the crystals develop over time. What Kashmir sapphires have are “Milky bands”, often only seen under the microscopic, that contain numerous nanoparticles. It is these minute particles that can refract light to create a “glow” similar to the effect you see in moonstones.
Kashmir sapphires are also more likely to contain pargasite needles that clump together and tourmaline, feldspars and zircon inclusions. These inclusions are not exclusive to only Kashmir sapphires so it is multifaceted review of all aspects of the sapphire to attribute an origin. So that requires a top reputable lab with lots of expertise to ”trust” the designation of a Kashmir origin.

 

[Beautiful-disaster]

I should say - I don’t think mine is of Kashmir origin. I just found they were the ones that consistently showed the colour change like mine did.
Taking in what you have said I’m thinking I’m not seeing it in other Sapphires because it’s only acceptable in the proven valuable ones (due to origin and size) - where as it would largely devalue a smaller sapphire of different origin.
I’m in Sydney Australia - our best Gem Lab is close but I’m self isolating as much as possible so I’m waiting to have it evaluated there when I can take it in myself. Also my business has been closed since March so it isn’t an expense I can justify right at this moment.
I’m using it to learn atm.
I have a non digital calliper and some loops, a diamond tester and Digital scales. But would like to upgrade them to better ones. I’m amazed at how just a few weeks of looking and learning has made my eyes so much better at recognising quality stones. (Obviously more to learn then you could hope to in a life time!) - but I do really appreciate how free the people are here with information when I find myself stuck.
Thanks again.

 

[Bron357]

I should say - I don’t think mine is of Kashmir origin. I just found they were the ones that consistently showed the colour change like mine did.
Taking in what you have said I’m thinking I’m not seeing it in other Sapphires because it’s only acceptable in the proven valuable ones (due to origin and size) - where as it would largely devalue a smaller sapphire of different origin.
I’m in Sydney Australia - our best Gem Lab is close but I’m self isolating as much as possible so I’m waiting to have it evaluated there when I can take it in myself. Also my business has been closed since March so it isn’t an expense I can justify right at this moment.
I’m using it to learn atm.
I have a non digital calliper and some loops, a diamond tester and Digital scales. But would like to upgrade them to better ones. I’m amazed at how just a few weeks of looking and learning has made my eyes so much better at recognising quality stones. (Obviously more to learn then you could hope to in a life time!) - but I do really appreciate how free the people are here with information when I find myself stuck.
Thanks again.

Hi, I’m in Sydney too. We don’t have a “GIA” or “AGL” here in Australia. We need to use Bill Sechos from Gem Studies Laboratory. He is very experienced and well regarded. But if you want or need a “name lab” you probably need to consider Lotus Gemology in Bangkok. I intend to take my Rubies there in person once this craziness of Covid is over.

 

[Beautiful-disaster]

Yes I was planning on taking it to Gem Studies Lab in Pitt street. I’m not planning on selling it. (Unless it miraculously turned out to be work six figures - hahaha) - but we do want to have to repolished, valued, the setting fixed and it reset and insured for the moment. It’s inherited and super sentimental.

 

[Beautiful-disaster]

*** worth


I must say I couldn’t get approximate pricing for this online? (Just the Lab).

 

[LilAlex]

Yes, it is generally undesirable. I don't like sapphires that "pop into focus" as you rock them and suddenly show intense blue whereas they are pale and watery at every other angle. Clever cutting and they are graded face-up and on-axis but that's now we generally look at our rings, etc.

Edit: ...and those are "Kashmir" in name only. Please post those the next time someone says they want a Kashmir sapphire. Most "online" Kashmirs are terrible now.

 

[Beautiful-disaster]

Yes, it is generally undesirable. I don't like sapphires that "pop into focus" as you rock them and suddenly show intense blue whereas they are pale and watery at every other angle. Clever cutting and they are graded face-up and on-axis but that's now we generally look at our rings, etc.

I’m finding rather the opposite in my taste. When they have the overall even saturation they look simulated to me. But I don’t have a trained eye to pick out an amazingly perfect natural sapphire over a simulated one. So the natural inclusions and personality traits make it more individual and unique to me as long as it’s not effecting the clarity and sparkle of the stone.

 

[Bron357]

Yes I was planning on taking it to Gem Studies Lab in Pitt street. I’m not planning on selling it. (Unless it miraculously turned out to be work six figures - hahaha) - but we do want to have to repolished, valued, the setting fixed and it reset and insured for the moment. It’s inherited and super sentimental.

Bill can give you a complete Gem report but he doesn’t provide valuations or repolishing service.
You should contact Doug Menadue at Bespoke Gems. He is a cutter and also refurbishes gemstones. He’s very very good. He’s also in the City. I’ve been to his office, up 5 flights of stairs cos the lift was out. Nearly killed me as it was summer and their Air con was out too!
Doug should repolish before Bill because the carat weight might change (very small amount). If you don’t have a jeweller I can recommend Jarret Jewellers at Town Hall (in the arcade under Sydney Town Hall). They can repair the setting and give you a valuation for insurance purposes. I’ve been using them for nearly 20 years now. They have done multiple repairs and remodels for me.

 

[Bron357]

Some of Jarrets work for me,

 

[Beautiful-disaster]

Some of Jarrets work for me,

Wow you certainly have some lovely pieces
Thankyou very much for the recommendations.
I do have a jeweller that I trust as he hand made my engagement ring with a hearts and arrows diamond 15 years ago. We were very naive and he sold us a very high quality piece for an awesome price which I have found to be not the *norm* in the world of Jewellery stores. He is the only one I trust to clean and my ring for me. He is in Dulwich Hill - but not online - too old school for that.
I will definitely seek the polishing before taking it to the lab (great point about the ct weight that hadn’t occurred to me although it’s obvious). I don’t mind losing a little but would prefer it stay at 8cts if possible (so a re-polish maybe off the cards - I know a recut it, and to be honest I like the old cuts. -especially in vintage style pieces. I just want to do right by the stone at this point.
Having it out of the setting has allowed me to appreciate it.
Up until now I had been told it was only worth sentimental value (which is a lot to me as it came from my father and he died when I was young). So I’m not holding any great hopes as to it’s value.
I am finding all about its inclusions and silks fascinating .... but just couldn’t get the info on dichroic gems to start to understand this element.
I have never seen it in a Ruby for instance which I know is essentially a red sapphire. This conversation has been very informative on so many levels.

 

[Beautiful-disaster]

Oh here it is with it’s broken setting.
the jump loop broke and I stood on it! - but I’m glad I did or I may not have noticed and it would have been gone forever!
So now the prongs need to be rebuilt and new jump loops at a minimum.
She is beautiful though and seriously glows under different lights - also the largest real gemstone I have seen in real life - so nice to play with! - lol

 

[Bron357]

Doug is a lovely person. He specialising in cutting Sapphires and his work is beautiful.
I think all you’ll be needing is a repolish of the facet edges to removes the little nibbles. That won’t take much off your sapphire, maybe 10 to 20 points, so that’s still over 8 carats.
Obviously changing the cut or facets results in more loss, no harm asking Doug about it, he‘ll give you his honest opinion as to what will work and what won’t, sometimes it’s worth the weight loss to dramatically improve the performance of the gemstone.
this if off his website.
and great you have a reliable jeweller. Worth their weight in gold ha ha.

 

[Bron357]

And your sapphire most certainly has a good $$$$ value. Over 8 carats and unheated, once it’s been restored to its full glory by Doug, I’d say over $20,000 even with its colour zoning.
If it is Kashmir (and Bill will know, he’s IDed Kashmir before) it is probably over $100,000!

 

[Beautiful-disaster]

Doug is a lovely person. He specialising in cutting Sapphires and his work is beautiful.
I think all you’ll be needing is a repolish of the facet edges to removes the little nibbles. That won’t take much off your sapphire, maybe 10 to 20 points, so that’s still over 8 carats.
Obviously changing the cut or facets results in more loss, no harm asking Doug about it, he‘ll give you his honest opinion as to what will work and what won’t, sometimes it’s worth the weight loss to dramatically improve the performance of the gemstone.
this if off his website.
and great you have a reliable jeweller. Worth their weight in gold ha ha.

Wow what a dramatic difference! I will definitely go and look at his website and hope I will be able to afford his expertise! Thankyou so much.

 

[Beautiful-disaster]

Edit: ...and those are "Kashmir" in name only. Please post those the next time someone says they want a Kashmir sapphire. Most "online" Kashmirs are terrible now.

Would you mind explaining what you mean by *Kashmir* in name only? They are identified as Kashmir in origin (and the prices reflect that). They have a lot of really nice sapphires but only 4 that are identified as Kashmir.
Here is a link to one of themhttps://www.thenaturalsapphirecompany.com/3.04ct-kashmir-cushion-blue-sapphire-b11832-/
I do know a lot of people use it as a colour - like Royal, Cornflower, Ceylon etc is this what you thought I meant?
Sorry I’m actually confused by your comment.

 

[Beautiful-disaster]

@Bron357
I wonder if you would mind telling me about the stone in this gorgeous ring. I have been looking for an emerald with the same sort of cut to replace the one that broke in my mothers engagement ring for my sister. I have been looking at emerald cuts but they all seem too deep and not quite right for the setting.

 

[Bron357]

My engagement ring. It’s an Art Deco emerald cut, quite different proportions to how most are cut these days. It’s 4.35 carats. I love low profile rings because I’m clumsy ha ha. it was my “design” and my jeweller sourced the extra side stones for me. Just a bit different.

And about Kashmir sapphires. The fabulous ones were mined out over 100 years ago. They do still mine in the region but the quality is nothing like the old stock.
It is the colour, best described as Vivid Velvet blue, combined with the nanoparticles that reflect light, that give such sapphires their unrivalled reputation. These days, top Burmese sapphires and even Ceylon Sapphires can match the hue and tone but only Kashmir’s have the magic glow.

 

[Beautiful-disaster]

My engagement ring. It’s an Art Deco emerald cut, quite different proportions to how most are cut these days. It’s 4.35 carats. I love low profile rings because I’m clumsy ha ha. it was my “design” and my jeweller sourced the extra side stones for me. Just a bit different.

And about Kashmir sapphires. The fabulous ones were mined out over 100 years ago. They do still mine in the region but the quality is nothing like the old stock.
It is the colour, best described as Vivid Velvet blue, combined with the nanoparticles that reflect light, that give such sapphires their unrivalled reputation. These days, top Burmese sapphires and even Ceylon Sapphires can match the hue and tone but only Kashmir’s have the magic glow.

It’s a gorgeous ring. So it’s just a matter of searching until I find a low profile one I guess.
Thanks so much.
*****
Yes I was aware with the colour thing with Kashmir - are you trying to tell me the company isn’t a reputable one or something? or that the examples they have aren’t good ones?
I feel like I’m missing something.

 

[Bron357]

The Natural Sapphire Company, if that’s who you are referring to, apparently had a few issues a while back. The Principle had a few legal problems with how he was running the business.
I don’t think they are on the “recommended” PS vendor list, the prices are very high for what they sell.
The Kashmir sapphires they are selling come with the preferred top lab certificates confirming their Kashmir origin so they are Kashmir. Are any of them “great” examples ? In my humble opinion, no. They are pretty average looking and without a Kashmir label they’d be 1/4 the price.
People pay a premium for the Kashmir label but I think it’s only worth it if the sapphire displays all the attributes that Kashmir sapphire are revered for and that is the amazing vivid blue that glows.

 

[Frost]

Just to reiterate something: absolutely every origin on the planet is capable of, and moreover likely to, show color zoning/banding/milky-silky bands etc. The vast majority of sapphires that come out of the ground anywhere look nothing like finer examples online, and much more like the several color zoned samples in OP's post.

You wouldn't know it from looking at gems online, but in person as you examine stones from different sources you quickly realize that there is no such thing as exclusive inclusions or features when it comes to blue sapphire... There's only degrees of likelihood.
Burmese stones can look like Sri Lankan ones, which can look like Madagascan ones, which can look like Kashmir ones. There's literally no way to be 100% sure without either seeing it come out of the mine yourself or getting a big name lab report (or several, if it's a particularly fine Kashmir).

Another small addition - sapphires from other sources can and very much do show the exact same type of glow that made Kashmir famous over time.

Microscopic rutile silk is found in all sources, but if we're being particular, Elahera in Sri Lanka and Bemainty in Madagascar have both famously produced stones which had labs fooled for years on end, and both those origins have received Kashmir reports. And similarly, I've owned a stone from Nivithigala in Sri Lanka that got a big-lab Burma report, for example.

It is a visible difference though - ultra-fine silk produces a glow quite unlike most other things, and those stones cost significantly more even when being sold as being from those sources i.e. not misidentified as Kashmiri. And it has to be just the right amount too - none equals no extra saturation, too much equals just too silky/sleepy.
In other words, there are non-Kashmir stones identical to Kashmir ones out there, but they are extremely rare, just like the finest from Kashmir itself.

GIA, GRS, Lotus and others had some publications on the topic, it was a big talk a few years ago because Kashmir reports were being issued for stones that looked identical but actually weren't.

The only way to be really safe would be trace element analysis/quantification, and it's pretty much only worth it if one really wants to pay that Kashmir premium for an actual premium stone - which, in stones of fine quality à la the ones being sold at Christie's or Sotheby's, is about 10x or so (100,000 - 150,000 USD/ct. for 10+ ct. vs. 10-15k/ct. for other origins).

 

[Beautiful-disaster]

The Natural Sapphire Company, if that’s who you are referring to, apparently had a few issues a while back. The Principle had a few legal problems with how he was running the business.
I don’t think they are on the “recommended” PS vendor list, the prices are very high for what they sell.
The Kashmir sapphires they are selling come with the preferred top lab certificates confirming their Kashmir origin so they are Kashmir. Are any of them “great” examples ? In my humble opinion, no. They are pretty average looking and without a Kashmir label they’d be 1/4 the price.
People pay a premium for the Kashmir label but I think it’s only worth it if the sapphire displays all the attributes that Kashmir sapphire are revered for and that is the amazing vivid blue that glows.

Can you please tell me where I can find the recommended vendor list? I have had a look but can’t locate it. A lot of the other vendors I have seen don’t show a pic or two of the gem. I liked being able to see the 360 and did think the site had some really nice stones.
(shows what I know).

 

[2Neesers]

PPS I’m also looking to buy digital calipers and a sonic cleaner if anyone knows where I may purchase these things that isn’t too expensive but also aren’t crappy quality. Is this one of those *you get what you pay for* things?

You‘re getting a lot of great help on your other questions, so I thought I would offer a recommendation on calipers. I really like the ones I’ve linked below because the measuring tips are a plastic type material. The calipers I had before, and most calipers I have seen have metal measuring tips, and I always worried they might scratch or chip the stone. This pair is compact, comes with a case and is gentler on stones, in my opinion .

General Tools 3 in. Carbon Fiber Digital Caliper 1433 - The Home Depot

General Tools has grown to become the recognized industry leader for specialty hand tools and instruments. The 3 in. Carbon Fiber Digital Caliper features an easy-to-read digital display that switches

www.homedepot.com

 

[Beautiful-disaster]

@2Neezers
Thankyou so much for that! They look perfect