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 Post subject: Malawi / Mozambique Stone
PostPosted: Fri Dec 12, 2008 5:13 pm 
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Hi all.

Can anyone help me ID this gem stone for me.

Image

Image

I got it off a dealer in Malawi who told me it was Tourmaline from Mozambique, I personally do not think it is Tourmaline.

The stone weighs 27 grams and is 43mm long.


Last edited by Tropheus on Sat Dec 13, 2008 5:28 am, edited 2 times in total.

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PostPosted: Fri Dec 12, 2008 6:24 pm 
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hi and welcome to our forum.
the picture you posted is too big, maximum width allowed in 450 pixel.
please, take the time to read here.
thank you
ciao :D
alberto

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Last edited by Alberto on Fri Dec 12, 2008 6:35 pm, edited 1 time in total.

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PostPosted: Fri Dec 12, 2008 6:34 pm 
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(while resizing)

... the color is fully possible for Mozambique (?) tourmaline (remembering a batch from H. Bosch, in particular ), but nothing of the appearance of the object indicates what it is. It could be some natural crystal, synthetic, or a shard of glass, or not even.

One can always guess, but I can't see anything conclusive. :? Now... the piece is large, so the fracture pattern hints at something else then tourmaline: as glass or quartz, it has conchoidal fracture, but tourmaline is more brittle so the 'look' is somewhat different with smaller, more angular bits. Would have expected some sign of dichroism in the picture if it were tourmaline, but it may escape... This is an irresponsible guess though for the sake of .. writing something longer.

As said. Nothing remotely conclusive. That's why most sellers do have liberal return policies, so you and your cutter can check. ;)

Besides, even if it is tourmaline, the picture doesn't show much about its clarity ... so potential use is also under question.

2c


Last edited by valeria102 on Fri Dec 12, 2008 6:45 pm, edited 1 time in total.

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PostPosted: Fri Dec 12, 2008 6:44 pm 
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Sorry about that RAVIRUS

I have re sized the image


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PostPosted: Fri Dec 12, 2008 6:52 pm 
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hi, Thanks :) ,
about your rough, from that picture i can't see much, can you perform some basic gemmo test, like for example searching for birifrangence?
this could help to exclude some materials like glass.
ciao
alberto

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PostPosted: Fri Dec 12, 2008 7:07 pm 
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Hi,

I have no test equipment. I was told it was Tourmaline from Mozambique, but I think that it is either quartz or citrine?


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PostPosted: Fri Dec 12, 2008 7:10 pm 
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you are spot on, it is a quartz: citrine (yellow quartz)...


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PostPosted: Fri Dec 12, 2008 7:13 pm 
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hi, citrine is a quartz.
hope some rough expert here could give some help although i can say that NO serious guess could be made only by a pic.
maybe you could submit your rough to some mineralogical associaton or to a gemologist close where you live.
ciao
alberto

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PostPosted: Fri Dec 12, 2008 7:34 pm 
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ey... ciò che ho appena detto?

:D


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PostPosted: Fri Dec 12, 2008 7:39 pm 
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hi mate, you were faster than me for few seconds... 8)
ciao
alberto

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PostPosted: Sat Dec 13, 2008 8:21 am 
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Hi,

Glass, fluorite, amethyst etc .. all placed in a coca bottle and shaken vigorously to round them a bit (make it look alluvial) .. then placed between the rest of the rough.

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PostPosted: Sat Dec 13, 2008 9:10 am 
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Hi Doos, Thank you for your reply,

Yes I agree, but this stone is not glass. There are a lot more of these stones but I picked the best coloured one for the photograph. The stone is 43 mm long and 26 mm thick, it has flat edges on it as well has sharp and rounded edges, this makes me feel that it would be difficult to achieve this with the coke bottle trick.

Are there any easy tests we can do to determine if it is glass or not, taking into account we are in Malawi with no test equipment available to us?


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PostPosted: Sat Dec 13, 2008 9:42 am 
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Allot more of them... That doesn't sound too encouraging: the color is somewhat unusual for tourmaline and I'd expect a large parcel of tourmaline to have various colors and sizes in it, some crystals etc. Of citrine you can get a bucket of chunks looking much alike and of matching color - no problem.

Without any instruments, tourmaline should still look dichroic: the stone should appear to have somewhat different color from two different directions. This should be quite easy to see, no squinting and second guessing necessary.

As said, considering the color in the pictures, I'd expect the 'other' to be a notably different shade of orange.

Since there is no synthetic tourmaline and no other stone does the same trick, this may solve the question of whether the material is tourmaline or not.

If you wanted to know what it is exactly, this is a different and more difficult question.

When writing the first post, I could only see the first picture. The second looks even more like quartz to me from the same reason (the shape of fractures).

I hope someone else volunteers a better answer...

Normally, you should be able to test the material. It isn't too responsible from my part to volunteer such a guess.


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PostPosted: Sat Dec 13, 2008 10:54 am 
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Thank you valeria for the tourmaline tip.

We were told that it was tourmaline but we are pretty sure that it is quartz. The other pieces do vary in shades of yellow and clarity. The photo is of one of the clear yellow stones, some of the other stones are less yellow with smokey appearance to them.

I am not after a 100% ID of the stone and was just hoping for some comments on them, and also to confirm that they are defiantly not Tourmaline.

Even so they are a very nice stone


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PostPosted: Sat Dec 13, 2008 11:45 am 
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Remember tourmaline is piezoelectric.
This is useful information. :wink:


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