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what to do about 'vulcanite'

Posted by Dona Leicht  
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Dona Leicht October 12, 2017 08:22PM
Everyday we get offers of 'fabulous', 'incredible', 'beautiful' specimens - rarely is there something of real value. I find that I have offended those people by having to tell them that their piece is hardly more than garden rock, let alone a collector specimen. The photo shows an example: this person claims this is a naturally occuring vulcanite which measures 9" x 9" - how to break it to them gently?? I hate to just ignore the e-mails. And just WHAT IS THIS piece really???

Thanks for some suggestions.

Dona Leicht
Kristalle

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Paul De Bondt October 12, 2017 09:33PM
Looks like man-made carborundum SiC ( silicium carbide )
Look at the blue hues on the base of the specimen.
I presume the specimen is quite light for it's size.

I hope this helps.

Paul.
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Pavel Kartashov October 12, 2017 09:43PM
Crystals on the sample are too large and well formed for carborundum. Besides that it is high lustrous and fluorescent in SW UV.

I bet for pyroxene crystals in metalurgical slag.

Photo of the back side of the item would helps.
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Kevin Conroy October 12, 2017 11:26PM
Dona, I think you can safely say that this isn't vulcanite. Send them the link for the mineral ( https://www.mindat.org/min-4213.html ), and maybe suggest that since there's a question about the identity that you're not interested in it at this point.
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Jolyon & Katya Ralph October 13, 2017 08:10AM
You can tell them it isn’t CuTe enough to be a vulcanite.



Edited 1 time(s). Last edit at 10/13/2017 01:20PM by Jolyon & Katya Ralph.
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Alfredo Petrov October 13, 2017 08:25AM
But if they have a vulcanite realgar, then we all want it.
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Joel Dyer October 13, 2017 12:01PM
Nice one, Jolyon :-)



Edited 1 time(s). Last edit at 10/14/2017 07:15AM by Joel Dyer.
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Ed Clopton October 13, 2017 12:16PM
Dirt or dust could account for the lack of the luster we expect from carborundum--this piece appears to have sat in a dusty place for some time--but more significantly, carborundum crystals tend to be thin tabular, and these look more wedge-shaped. I agree that it's probably not carborundum, but I can't guess beyond that. I don't suppose the owners have any info about locality or provenance . . . .
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Steve Hardinger October 13, 2017 01:52PM
Dusty hematite?
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Reiner Mielke October 13, 2017 02:30PM
Pavel,

I have seen many specimens with large well formed carborundum crystals. However they do look wedge shaped unlike carborundum. But it does look like some sort of artificial product



Edited 1 time(s). Last edit at 10/13/2017 02:32PM by Reiner Mielke.
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Donald Lapham October 13, 2017 03:05PM
I agree with the Silicon Carbide (Carborundum) ID. Living near Niagara Falls ON/NY they are plentiful up here. Many folks who worked at the old plants brought home the crystals that formed in gas cavities in the melt. Some specimens and individual crystals could get quite large. A good spray with water and it should return to a very sparkly beautiful piece.
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Mark Andrews October 13, 2017 03:37PM
Well done Alfredo. I see what you did there :-P

That joke is practically elemental.
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Dana Morong October 13, 2017 03:54PM
Maybe you could tell them that you only know and deal with minerals that are from Planet Earth.
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Bob Harman October 13, 2017 03:56PM
If SUPERMAN can be so intimately associated with kryptonite, then perhaps we should ask MR. SPOCK's opinion on VULCANite!
heh heh heh..... CHEERS......BOB
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Mark Heintzelman October 13, 2017 09:43PM
Agree with Donald, I've seen some with fairly large xtls as well. The only example image I have is a poor one, but this specimen is nearly 4 inches across.


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Jolyon & Katya Ralph October 13, 2017 10:12PM
No need to debate. Look at the photo carefully.

It 100% is a silicon carbide with flat hexagonal plates.

Ugly one though....
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Pavel Kartashov October 13, 2017 11:36PM
Yes, look at the photo carefully and you'll see that this isn't carborund. :)

I don't see any reaction of topicstarter. In such situation indeed any debates are excessive.
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Reiner Mielke October 14, 2017 01:03AM
Either way it is manmade and not worth worrying about.
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Uwe Kolitsch October 18, 2017 10:02AM
Possibly dull oxidised siderite?
Ask these people to check the hardness.
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