shape
carat
color
clarity

A very large faceted mineral/gem, uncertain as to what it may be

Headintheclouds

Rough_Rock
Joined
Jul 5, 2024
Messages
12
Hello one and all. Very pleased to have found this place yesterday.
I've been collecting antique jewelry for the past few years though not with any level of intensity.
A while ago I came across something very unusual which I ended up buying and have since enjoyed very much.
It seems to weigh around 600 grams give or take, has inclusions though very few in relation to it's size.

Appears to have been faceted in a rather rudimentary manner as the piece is uneven over all, it's not a perfectly symmetrical oval. Even so it is quite charming.

It had previously formed part of a collection of vintage and antique oval pieces, eggs and whatnot of different materials and apparent origins.

I was told by the seller who is an antiques dealer, that from what she had found out it could be a Tourmaline.

What say ye?
What is alarming is the amount of material present, if it is a gemstone, I think much of it of very decent quality.
I think it would need something of a facelift as it does poses some very small chips though these are few and far between.

My idea is to have it looked at at a lab when I next get to travel abroad. Hace it certified if warranted
1000070301.jpg View attachment 976202 View attachment 976202
 
Joined
Jan 20, 2012
Messages
4,741
Hmm interesting! Normally when a new member comes to show off their "special" stone, it is often a synthetic or common quartz crystal. But this may indeed be a natural specimen... and I think a good (preliminary) case could be made for tourmaline. I wonder if those inclusions are growth tubes or rutile? Look up trichites too, as they're pretty unique to tourmaline, and see if you can spot any under a loupe. If it is indeed earth-mined, you have a lovely piece there. I think it would be worth bringing to a local G.G. first, and then perhaps having a proper lab take a look at it if the G.G. feels it's natural. Remember, convincing lab-grown material and simulants abound, so be aware of that going in. I hope you'll return and let us know! Good luck!!

Also tagging one of our mineral experts to see what he might think... @PrecisionGem. But it's so difficult to confirm anything without examining in person.
 

Headintheclouds

Rough_Rock
Joined
Jul 5, 2024
Messages
12
The light brown colour that can be seen in the shape of hazy strips (just a few, towards one of the hemispheres) I would hazard a guess is due to the presence of some chemical substance be it metal in nature or other. But they do not appear to be inclusions per se, more like a second shade, making this, should it be so particoloured?

The inclusions seem to be small liquid or gas bubbles? Or maybe solid colourless mineral. They are not too prevalent within the bounds of the stone itself as I said before, nor do they appear to be round in shape. But this is all coming from someone who doesn't have the knowlege to determine these things beyond doubt. They may not be colourless but appear so due to the green blue overall colour of the stone.

 
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Joined
Jan 20, 2012
Messages
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If I -had to- name a gemstone it would probably be treated topaz. I think it's probably glass, though. Tourmaline that size isn't unheard of, but it's expensive and that color would be among the most desirable of colors.

This is true. And it is exceedingly clean... :think: Liquid and gas inclusions are pretty common in tourmaline. But bubble-like inclusions can also indicate synthetic spinel and corundum, etc. or glass simulants. I really hope OP takes it to a G.G., because I'm rooting for the elusive "hidden gem" post from a newbie!
 

Headintheclouds

Rough_Rock
Joined
Jul 5, 2024
Messages
12
Haha cheers. Will do and update. Can pretty much discard glass (I could be completely mistaken though)
. The inclusions aren't bubbles so much as droplets.
Anyway, whatever it is, it is that and I think finally drawing up the courage to share images of it publicly is testament to me coming to terms with that. It won't magically turn out to be something else for better or worse because I showed it and opened it up to scrutiny.

I may have certain hopes for it, but I am now calm in the knowlege that it won't be any more or any less what it already is. Except ofcouse for the monetary worth and the marvel that is nature should it turn out to be organic.

/Tipsy
 
Joined
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Messages
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Haha cheers. Will do and update. Can pretty much discard glass (I could be completely mistaken though)
. The inclusions aren't bubbles so much as droplets.
Anyway, whatever it is, it is that and I think finally drawing up the courage to share images of it publicly is testament to me coming to terms with that. It won't magically turn out to be something else for better or worse because I showed it and opened it up to scrutiny.

I may have certain hopes for it, but I am now calm in the knowlege that it won't be any more or any less what it already is. Except ofcouse for the monetary worth and the marvel that is nature should it turn out to be organic.

/Tipsy

I'm cheering for you! Good luck!!
 

Starstruck8

Brilliant_Rock
Joined
May 13, 2021
Messages
657
Interesting! The stained area near one end appears to be in a single plane. The end beyond the stained area appears to be lighter than the rest. (It is really?) This suggests natural zoning. As you say, the size is a worry - if it were anything more valuable than glass or quartz, it should have cost a fair bit...

Prasiolite (= heated amethyst) is a possibility. This is pale green, pretty inexpensive, and available in large sizes. N.B. this is no more than a guess.

A local jeweller or lapidary or someone at a local mineral/lapidary club may have a refractometer. This would easily rule out many possibilities.

Even before that, you could do some basic DIY gemmology. For example:

Just by heft, does it feel light, average or heavy for a rock of its size?

It's big enough that you could measure its specific gravity passably accurately with normal scales. You'll find instructions online. e.g. http://www.johnbetts-fineminerals.com/jhbnyc/articles/specific_gravity.htm

You may be able to check for double refraction and dichroism. Many LCD computer screens are polarized. You can check yours by holding polarizing sunglasses (or a polarizing camera filter) in front of it and turning them around. If you can get the screen to black out, it's polarized. Hold the stone in front of a white screen and turn it around. Does it change colour or tone noticeably with a 90-degree turn, then change back again with another 90-degree turn? If so, that's dichroism, which would rule out glass.

You can use the screen and polaroid sunglasses as a simple polariscope. (Again, look online for details.) Most basically: Turn the glasses to black out a white screen. Hold the stone in front of the screen and turn it around. If it stays black in all orientations, it's not doubly refractive. This would rule out quartz/prasiolite, topaz, tourmaline, zircon or any other doubly refractive stone. It would leave glass as the most likely possibility. N.B. If it doesn't stay black, that doesn't prove it's not glass.
 

Headintheclouds

Rough_Rock
Joined
Jul 5, 2024
Messages
12
Prasiolite does not appear to come in blue green, this stone also seems a little too intense colour-wise to be prasiolite. I could be wrong ofcourse.

The bottom/top are the same colour, no zoning that I can detect with the naked eye under ordinary light.

It is a pretty hefty thing, as I mentioned, must be around 600g give or take.

Will look intro the different testing methods you suggested, apreciate it very much.

There is a good chance this is a vintage or antique cut stone (or glass?), so the value of it is not as relevant as if it had been circulated amongst people with knowlege of such things. It was sold as an egg shaped object, probably mineral in nature (apparently it had been looked at by a Jeweler who said it could be Tourmaline "or another mineral", though the former owner did not remember which else it could be. She told me that having it seen at a lab and certified was too costly,but that it wasn't glass. Obviously this is all heresay, I do believe her but there is a chance she was simple wrong).

Anywhoo...
 
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Headintheclouds

Rough_Rock
Joined
Jul 5, 2024
Messages
12
Alright without intent of overloading this thread with nothing much, I took a few wonky pictures of 'the grenade', under bright light and magnified. It is only under these conditions that the stone takes on such a noisy interior appearance, though much of what can be seen is probably the same inclusions refracted a few times

The only inclusion visible under more normal conditions I have registered and can be seen in one of the images.

They seem to be tiny flakes, specks. I don't really know if they are such or are getting distorted by the facets. I thought they where droplet-like but now that I have looked at them under the loop I am not so sure now... 1000070479.jpg 1000070475.jpg 1000070473.jpg 1000070472.jpg
 
Joined
Jan 20, 2012
Messages
4,741
Alright without intent of overloading this thread with nothing much, I took a few wonky pictures of 'the grenade', under bright light and magnified. It is only under these conditions that the stone takes on such a noisy interior appearance, though much of what can be seen is probably the same inclusions refracted a few times

The only inclusion visible under more normal conditions I have registered and can be seen in one of the images.

They seem to be tiny flakes, specks. I don't really know if they are such or are getting distorted by the facets. I thought they where droplet-like but now that I have looked at them under the loop I am not so sure now... 1000070479.jpg 1000070475.jpg 1000070473.jpg 1000070472.jpg

May I ask where you live (generally speaking)? :)
 

Headintheclouds

Rough_Rock
Joined
Jul 5, 2024
Messages
12
This does feel like glass to me - reminds me of the type of "waviness" I see in faux-obsidian (or natural, I guess)

Got you. The only thing is it doesn't "feel" like glass in the hand for what it's worth. More importantly the edges are not dented or blunted that I can tell, which I have read is common in glass pieces. Then again it could be glass that has always been treated with care.

It did drop some time ago on hard ground (*shudder)
No damage caused.
Glass is a possible candidate then. Would the inclusions shown in the pictures be consistent with glass?
.
 
Joined
Jan 20, 2012
Messages
4,741
Currently Argentina, where I was born (though I grew up in France and England)

Hmm that's tricky. I'm trying to think of a convenient lab for you, but I can't come up with any (I would recommend) in South America. Still, there must be a trusted provincial lab or local G.G. who can give it a preliminary evaluation. I'm invested now! lol
 

Starstruck8

Brilliant_Rock
Joined
May 13, 2021
Messages
657
I came across this, which looks a lot like the material of your piece. Note the similar bubbles and streaks:
GlassPic.jpg

It's in a forum we are not allowed to link to, but it's about gemology and it's online. :twisted2: There is a subforum on glass and slag.

The experts there called it as glass. Are the brown streaks in your piece wavy and flowy as in this piece? If so, that would be pretty conclusive.
 

Headintheclouds

Rough_Rock
Joined
Jul 5, 2024
Messages
12
I came across this, which looks a lot like the material of your piece. Note the similar bubbles and streaks:
GlassPic.jpg

It's in a forum we are not allowed to link to, but it's about gemology and it's online. :twisted2: There is a subforum on glass and slag.

The experts there called it as glass. Are the brown streaks in your piece wavy and flowy as in this piece? If so, that would be pretty conclusive.

Awesome, appreciate the input. It does seem very similar in colour at least.
Could you define flowy?

In any case, the lines present here are pretty straight and uniform
 
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Headintheclouds

Rough_Rock
Joined
Jul 5, 2024
Messages
12
Hmm that's tricky. I'm trying to think of a convenient lab for you, but I can't come up with any (I would recommend) in South America. Still, there must be a trusted provincial lab or local G.G. who can give it a preliminary evaluation. I'm invested now! lol

Thank you! I plan to travel next year to the "first world" so maybe I'll pop down to the GIA offices and say what's cooking?
 

Daisys and Diamonds

Super_Ideal_Rock
Joined
Apr 30, 2019
Messages
23,582
Hello one and all. Very pleased to have found this place yesterday.
I've been collecting antique jewelry for the past few years though not with any level of intensity.
A while ago I came across something very unusual which I ended up buying and have since enjoyed very much.
It seems to weigh around 600 grams give or take, has inclusions though very few in relation to it's size.

Appears to have been faceted in a rather rudimentary manner as the piece is uneven over all, it's not a perfectly symmetrical oval. Even so it is quite charming.

It had previously formed part of a collection of vintage and antique oval pieces, eggs and whatnot of different materials and apparent origins.

I was told by the seller who is an antiques dealer, that from what she had found out it could be a Tourmaline.

What say ye?
What is alarming is the amount of material present, if it is a gemstone, I think much of it of very decent quality.
I think it would need something of a facelift as it does poses some very small chips though these are few and far between.

My idea is to have it looked at at a lab when I next get to travel abroad. Hace it certified if warranted
1000070301.jpg View attachment 976202 View attachment 976202

regardless of what it is, it is really pretty
i can see why you brought it
fingers crossed for you it is something exciting
but even if it turns out to only be glass, as i said it is still really pretty
i love the cut on it
and the colour is gorgeous
and of course the size is wonderful
good luck

please remember to come back and tell us
i have an old ring i was hoping was going to be synthetic tourmalin,
alas she was just glass, (pretty glass)
but i must still love her, because i talk about her a lot :lol-2:
 

Daisys and Diamonds

Super_Ideal_Rock
Joined
Apr 30, 2019
Messages
23,582
I came across this, which looks a lot like the material of your piece. Note the similar bubbles and streaks:
GlassPic.jpg

It's in a forum we are not allowed to link to, but it's about gemology and it's online. :twisted2: There is a subforum on glass and slag.

The experts there called it as glass. Are the brown streaks in your piece wavy and flowy as in this piece? If so, that would be pretty conclusive.

i would buy that just to sit on my kitchen windowsill !!
 
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