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Is this a spinel or rubellite tourmaline?

paragon1234

Shiny_Rock
Joined
Mar 8, 2020
Messages
203
I know everyone loves a "what is this stone" thread without seeing it in person or having a lab check it :Dbut here is mine.

I bought this 18ct gold pendant with no hallmarks and a 5mm red/pink stone on eBay. The gold was tested. The stone looks really vivid in some lights and meh in others. It has at least one black inclusion and a small window so not cut very well. It fluoresces vividly under UV light. I took some photos under 40x loupe.

The seller told me it was rubellite. I think they used a Presidium tester on it, which presumably can differentiate between corundum and not.

I don't know if a Presidium tester can differentiate between spinel and tourmaline. I thought rubellite tourmaline doesn't fluoresce under UV so I think it's a spinel. Any other opinions?
IMG_20210730_093344__01.jpg IMG_20210730_093508__01.jpg IMG_20210730_093528__01.jpg IMG_20210730_093645__01.jpg IMG_20210730_121705__01.jpg IMG_20210730_122756__01.jpg IMG_20210730_123804__01.jpg
 

voce

Ideal_Rock
Joined
May 13, 2018
Messages
4,822
I know everyone loves a "what is this stone" thread without seeing it in person or having a lab check it :Dbut here is mine.

I bought this 18ct gold pendant with no hallmarks and a 5mm red/pink stone on eBay. The gold was tested. The stone looks really vivid in some lights and meh in others. It has at least one black inclusion and a small window so not cut very well. It fluoresces vividly under UV light. I took some photos under 40x loupe.

The seller told me it was rubellite. I think they used a Presidium tester on it, which presumably can differentiate between corundum and not.

I don't know if a Presidium tester can differentiate between spinel and tourmaline. I thought rubellite tourmaline doesn't fluoresce under UV so I think it's a spinel. Any other opinions?
IMG_20210730_093344__01.jpg IMG_20210730_093508__01.jpg IMG_20210730_093528__01.jpg IMG_20210730_093645__01.jpg IMG_20210730_121705__01.jpg IMG_20210730_122756__01.jpg IMG_20210730_123804__01.jpg

The presidium tester is no good for differentiating between colored gems. That is a synthetic ruby, most likely, although you can't prove it unless you pay $$$ to send the getting to a lab.
 

fredflintstone

Shiny_Rock
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Jul 18, 2020
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372
The higher end Presidium testers using both thermal conductivity and R.I. can differentiate between many colored stones. Just not most lab created stones vs. natural. But a knowledge of inclusions can greatly help the identification process. The new R.I. feature can help on some on lab created. Tourmaline is not available commercially lab created.


Rubellite is a subjective term. Some labs/dealers consider any pink to red Tourmaline Rubellite. In my opinion if Tourmaline I would call it a hot pink but not Rubellite. Rubellite means "Ruby like," This stones color is more akin to hot pink Sapphire.

No one by a pictures can identify this stone positively. You need a gemologist.
 

paragon1234

Shiny_Rock
Joined
Mar 8, 2020
Messages
203
So should I expect that synthetic rubies and spinels could contain black inclusions then? I read previously on this forum that synthetic stones are generally too perfect.
 

voce

Ideal_Rock
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So should I expect that synthetic rubies and spinels could contain black inclusions then? I read previously on this forum that synthetic stones are generally too perfect.
They could theoretically, but it's less likely. However, your pictures do not show any black inclusions. The shadowed spots in certain pictures are simply indications of light leaking out due to the cut of the stone, not due to inclusions. Have you browsed a lot of antique jewelry shops in Etsy? Many of them sell vintage rings set with synthetic rubies, and many of them are dead ringers for what you're showing us here in this thread.
 

Bron357

Ideal_Rock
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5,518
Hi, firstly the bail of the pendant is marked 750 so that’s 18ct gold.
Rubelite/ pink / red tourmaline does not fluoresce under UV. So your gemstone can’t be tourmaline.
Spinel and Sapphire, whether natural or lab, do fluoresce under UV so your gemstone is likely either spinel or sapphire.
A Presidum tester can differentiate between many gemstone types, based on the different rates of thermal transition, but it can’t differentiate between earth found and lab grown material. It can be a useful tool for IDing CZ vs anything else, garnet from other red gems, amethyst from other purple gems but it’s not a recognised gemologist tool.
Gemologists conduct a number of tests/ observations to identify gems including calculating Specific Gravity, using a Spectroscope, UV reaction, magnetism and most importantly observation of inclusions.
In natural sapphire it is unlikely you’ll find ”black” inclusions however spinel can contain graphite so a “black” inclusion is more likely in Spinel.
Lab grown material can be incredibly convincing as it will “match” earth found material except when observed under a microscope.
Unless you have the correct equipment for analysis and acquired knowledge and experience it’s not really possible without a reputable lab certificate to be certain of the gemstone and it’s treatments.
Depending on the purchase price, you could send it to AGL, as they can provide a Brief report for a mounted gemstone. Other labs might require the gem “unmounted” ie taken out of the setting. That’s added expense.
So unless you must be certain of gemstone ie because you paid a lot of money for it I would just love and enjoy its beauty.
 

paragon1234

Shiny_Rock
Joined
Mar 8, 2020
Messages
203
They could theoretically, but it's less likely. However, your pictures do not show any black inclusions.

I've circled the biggest visible black spot. It's quite hard to take a photo with a mobile phone through a loupe - what I can see clearly with the eye is hard for the phone to focus on.
IMG_20210730_123804__01__01.jpg
 

voce

Ideal_Rock
Joined
May 13, 2018
Messages
4,822
I've circled the biggest visible black spot. It's quite hard to take a photo with a mobile phone through a loupe - what I can see clearly with the eye is hard for the phone to focus on.
IMG_20210730_123804__01__01.jpg

Those don't look to me to be like black inclusions. They could be inclusions of other varieties reflecting light out of the sides, or things on the underside of the stone. If your stone is natural, it looks like it's Burmese spinel or Burmese sapphire/ruby. To me it looks like a hot pink sapphire, but if course some phones make reds look pink. Either way, if natural, this stone is pretty valuable.

The only thing certain is that it's not a tourmaline. Sorry but the person selling you this is not well versed when it comes to colored stones.
 

LD

Super_Ideal_Rock
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Joined
Jun 29, 2008
Messages
10,156
It’s definitely not a Rubellite. What would make me lean to a synthetic if someone description is the lack of knowledge from the seller (using the wrong tools and even suggesting Rubellite etc). If you didn’t pay much for it and like if whether it’s synthetic or not, just enjoy it x
 

paragon1234

Shiny_Rock
Joined
Mar 8, 2020
Messages
203
Hi, firstly the bail of the pendant is marked 750 so that’s 18ct gold.
Rubelite/ pink / red tourmaline does not fluoresce under UV. So your gemstone can’t be tourmaline.
Spinel and Sapphire, whether natural or lab, do fluoresce under UV so your gemstone is likely either spinel or sapphire.
A Presidum tester can differentiate between many gemstone types, based on the different rates of thermal transition, but it can’t differentiate between earth found and lab grown material. It can be a useful tool for IDing CZ vs anything else, garnet from other red gems, amethyst from other purple gems but it’s not a recognised gemologist tool.
Gemologists conduct a number of tests/ observations to identify gems including calculating Specific Gravity, using a Spectroscope, UV reaction, magnetism and most importantly observation of inclusions.
In natural sapphire it is unlikely you’ll find ”black” inclusions however spinel can contain graphite so a “black” inclusion is more likely in Spinel.
Lab grown material can be incredibly convincing as it will “match” earth found material except when observed under a microscope.
Unless you have the correct equipment for analysis and acquired knowledge and experience it’s not really possible without a reputable lab certificate to be certain of the gemstone and it’s treatments.
Depending on the purchase price, you could send it to AGL, as they can provide a Brief report for a mounted gemstone. Other labs might require the gem “unmounted” ie taken out of the setting. That’s added expense.
So unless you must be certain of gemstone ie because you paid a lot of money for it I would just love and enjoy its beauty.

Thank you @Bron357 for writing such a detailed answer. I'm here to learn :)

My question is academic as I paid £180 for it - not worth sending off to be certified. I don't expect to have bagged the steal of the century. On eBay it's caveat emptor, and I only always pay the scrap value of the gold plus a token amount for the craftsmanship and for a pretty stone of unknown provenance.

As an aside, most UK jewellery sellers don't mention stone treatment/origin. I guess the UK consumers don't know/care to ask such questions.
 

Rfisher

Ideal_Rock
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Oct 19, 2013
Messages
3,846
I’m no inclusion expert - but I will ask
Does the black/dark inclusion have sharp borders
Or are they a bit fuzzy/blended in at the edges and maybe a bluish black?

Pretty stone/pendant!
 

paragon1234

Shiny_Rock
Joined
Mar 8, 2020
Messages
203
I had some fun tonight trying to take photos with a macro lens and a loupe. I had to turn the aperture to wide open and shutter speed right down and I did it without a tripod, i.e. I used my hands to hold the camera, the loupe, and a finger on the pendant to stop it from moving. Had to take photos on an exhale :D

The inclusion looks rather like a bird in flight, or a seed head floating in the wind. There are some other things that look like tubes?

DSC_5330.JPG DSC_5332.JPG DSC_5337.JPG DSC_5340.JPG DSC_5342.JPG
 
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