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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Mon Feb 06, 2017 4:54 pm 
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On my monitor, the first 2 pictures appear rather light.
Not so on the last posted ones, so I don't know which ones should be trusted.


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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Mon Feb 06, 2017 9:12 pm 
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Thank you for the replies.

I got the lab brief. It tested as no indication of heat treatment, with healed fracture (healing feathers tend to be seen in Thai stones). This lab has identified synthetic and heated stones for me before.

Regarding the color, the stone came from the Bang Kacha mine in Chanthaburi which produces saturated whiskeys and canaries, and yellow green colors. Unlike stones from other sources like Madagascar, Ceylon, and Montana, Thai yellows tend to be a darker or brighter yellow.

However, the locals prefer the "Mekong Whiskey" color.

http://www.lotusgemology.com/index.php/lab/color-types

The untreated canary and sunshiny colors are usually directly bought by traders from India from miners/cutters in Chanthaburi. Untreated yellow sapphires or 'pukhraj' play an important role in Vedic astrology and worn as a lucky stone (stone of the benevolent planet Jupiter), sought after like jade in Chinese Culture. Like Jade for Chinese, the stones have to be untreated though.

I got this specific lot from an old time dealer in Chanthaburi who has access to the factory (miner/cutter - they call it factory). Nevertheless, the bright traditional heat-only yellows (locally called old heat, as differentiated from diffused, coined as new heat) are easily available around the country and sold at affordable prices, because the whiskey-colored stones are those that command a premium so I've been getting my hands on a few of these stones (IMHO, the canaries are brighter and look waaaaay better than the whiskey!)

Anyhow, to show you the color, I have placed a "post-it" colored yellow paper as color reference for the stones as well as a photo of the lab brief.


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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Tue Feb 07, 2017 1:09 am 
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So unheated... sounds very good.

I like this kind of yellow sapphire - I have a 2,7 ct "whisky" colored one but from Sri Lanka, unheated imo course many sharp negative crystal. But "your" color is very nice.

Easily available and sold at affordable prices means how much per carat?

Would be interesting....

And other colors?

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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Tue Feb 07, 2017 4:30 am 
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Seaglow wrote:
More photos...

what are those blue stones? i guess you got wrong upload?

i personally not familiar with CGT lab, good luck with your Yellow Sapphires.

regarding "Mekong Whiskey" i am not sure if your stone goes into that category, we classify Mekong Whiskey more like Luminous brownish tangelo color! yours has more dark yellow as dominant color

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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Tue Feb 07, 2017 5:45 am 
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Hi Marlow,

The stones, eye clean heated ones over a carat and less than 3 has a typical asking price of 100-200/carat. You haggle your way down. Lesser quality stones of less than a carat to less than 1.5carats, easily 10-50/carat. Other stones sold with current yield are green and black star sapphires. The green tend to be a dull or olive green though, and many are made into cabochons. There used to be more jasmine greens (a lighter color) but current mine output are darker colored.

Yes, I've seen whiskey color from Ceylon origin, and not impossible at all as Ceylon produces nice natural-colored oranges, there can be also bright yellows but most are light colored. :)

Hi Roshanravan,

Thanks. :) I had another message before the blue stone photos. I was saying there is a similar inclusion in the blue stones similar to the yellow stone....and yes, the stones are definitely not Mekong Whiskey. There is a premium for Mekong Whiskey color locally, and I prefer the canary and lighter ones that are priced less which works for me. CGT lab is the only lab in Chiang Mai area, and I would definitely use well-known labs when in Bangkok as the rates are the same.


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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Tue Feb 07, 2017 6:55 am 
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Seaglow wrote:
....
Hi Roshanravan,

Thanks. :) I had another message before the blue stone photos. I was saying there is a similar inclusion in the blue stones similar to the yellow stone....and yes, the stones are definitely not Mekong Whiskey. There is a premium for Mekong Whiskey color locally, and I prefer the canary and lighter ones that are priced less which works for me. CGT lab is the only lab in Chiang Mai area, and I would definitely use well-known labs when in Bangkok as the rates are the same.

i agree bright Yellow and Canary Yellow are much prised and rarer, also i like orange colors instead of Whiskey colors

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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Tue Feb 07, 2017 7:26 am 
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Yes, this color is closer to a fine Sauternes. I like them both.

Heated means def. no Beryllium treatment?

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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Tue Feb 07, 2017 8:57 am 
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Yes, not BE. Though the bright yellows are rare, not so for the Bang Kacha mine to produce the color.

I searched the net for bright yellow sapphires and I see most stones are from Ceylon and not of Thai origin (I cannot access a couple of big Thai online stores when in Thailand, they restrict access when in-country so I cannot see what they have). Thai and Burmese stones are being bought at mines I heard by dealers from China and India...(Thai dealers had less access to Burmese stones when Myanmar opened their trade) but long established Thai dealers still get a portion, thus it is across Thailand.


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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Sat Apr 01, 2017 11:13 am 
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While looking around the markets in Thailand, I have noticed that there were a lot of yellow and green sapphires. When I see yellow, my first assumption would be BE treated, as many are quite bright. But all the reputable sellers and cutters I have asked would insist that they were 'old heat' Thai sapphires. Small stones under a carat were common, even set in silver. To my knowledge, the mines now don't produce much, if any. But the availability is around. But I've noticed one thing. They are usually cut on the shallow side.

Upon further prodding, I got to know that there was a new mine not so long ago in Chanthaburi and now also not producing as it used to. I have reserved to get a bigger green and yellow sapphire preferably over 10 carats. And I found out the reason why stones were on the shallow side. Most stones are bi-colored, with the greens on the darker side. The factory cuts them by separating the yellows and the greens. The stones are heated, and now cut stones are seldom above 10 carats.

Here are a couple of stones that I got. I wanted a brighter yellow which I passed up because the factory cuts for weight retention, and in most cases, the pavilion is not centered and many cuts are not symmetrical. So instead I got a green that was lighter than the usual yield and a Mekong Whiskey color, weighing 6+ and 5+ carats, respectively.

Here are photos showing roughs and cut stones and my purchases. The bi-colored stones are the unheated roughs and the pile of cut stones on the left of the photos are after heating.


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Last edited by Seaglow on Sat Apr 01, 2017 11:48 am, edited 3 times in total.
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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Sat Apr 01, 2017 11:18 am 
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More photos...

My purchases...quite windowed, I know, but the factory don't want to sell their roughs, and one has to have it recut to take out the windows. I've had some of my smaller bright yellows from the factory recut. I got the cleaner stones from the current yield.


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Last edited by Seaglow on Sat Apr 01, 2017 11:49 am, edited 4 times in total.
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 Post subject: Re: Yellow Sapphire - Heat, Unheated, or BE Treated?
PostPosted: Sat Apr 01, 2017 11:20 am 
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And Some more photos...the thing about many local lab briefs is that most sellers would leave the comments section blank, which IMHO, becomes useless. It has been a regular practice unless the stones are untreated. It is easier to sell the stones as it says 'natural sapphire' especially if the stones are glass-filled, or diffused. Some labs charge more to put the comments. At least, the only thing it guarantees is the stones are not synthetic. Still, the price difference between stones of varying treatments can be substantial. When in doubt, I get another report from a reputable international lab after recutting.


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