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Lapidary / Gemstone Community Forum
January 16, 2019, 06:19:07 pm
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1890 Minerals from Jeweler labled "Carbon" but they shine like Diamonds

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Author Topic: 1890 Minerals from Jeweler labled "Carbon" but they shine like Diamonds  (Read 151 times)
rob71
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« Reply #15 on: December 13, 2018, 10:49:45 pm »

Debbie , I think they nailed it over on the other site.

Here is one of the replys after I said ,. I guess it is not a jackpot.


Well, an early example of carborundum would be at least a small jackpot - historic value, and you have some documentation and history to go with your sample(s). A keeper. Santa came early on that one.

It is the first carborundum so I have no idea what that would do to the Value.

I scratched a bottle very easily with it .. it is very hard and jagged here is the photo.



* 99.jpg (183.06 KB, 1080x1440 - viewed 3 times.)
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rob71
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« Reply #16 on: December 14, 2018, 07:31:13 am »

Debbie they are kind of torn on the value of these.

One person says put them back.. another person says they are a small jackpot because they are the first of this mineral and differ.

I agree that they are carborundum but the mineral is still different in appearance.


Does carborundum set of a Diamond tester? I might buy some and compare it.
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Debbie K
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« Reply #17 on: December 14, 2018, 09:09:49 am »

Rob:

What other site are you referring to? Are they gemologists?

You really need to find a gemologist who has a Raman spectroscope or a university in your area that does to identify this. All we can do is say "This looks like..."

BUT, your rocks set off a thermal diamond tester for diamond, and so will Carbonado.

It's Carbonado, not Carborundum.

Since your rocks were in the possession of a jeweler in the 1890's, this really doesn't help establish provenance. If the tin said "Carbon - Brazil" or "Carbon -Africa" that perhaps would. Carbonado was first found in Brazil, and if this is what they are, it's likely that's where they're from.

From my understanding of this stone, if it is carbonado, it's only really value is as a mineral specimen, as it is too hard and often too porous to polish/facet well. But don't underestimate that market.

Find someone in your area who is an expert; either mineralogist or gemologist and have them look at them. Do not listen to anyone on the internet who tries to give you a positive ID on a picture alone, it simply isn't possible. When you said (and showed) your diamond tester lit up for diamond, that's why I ventured an opinion. Also, the appearance of yours is different; it is much more crystalline and may be much more unusual.

Really, truly, try to find experts in your area. These look to me like they are pretty cool and different. I'd love to see a close up of them. If you find a gemologist in your area, see if they can do a specific gravity test, as carbonado has a SG of 3.52 + or- .01, which is a really narrow range and pretty diagnostic.

Debbie
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slabbercabber
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« Reply #18 on: December 14, 2018, 06:00:17 pm »

If you want to be sure it is not grinding slag you can first try a strong magnet.  Carbonado is non magnetic.  An even more certain test is acid.  Any metal that has been ground will fiz.
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Debbie K
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« Reply #19 on: December 14, 2018, 06:28:46 pm »

Here are two more interesting articles/papers on carbonado:

https://www.gia.edu/gems-gemology/summer-2017-carbonado-diamond
http://www.geologyin.com/2015/10/what-are-black-diamonds-and-how-do-they.html

I think the acid test is a good idea, too.

Debbie
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rob71
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« Reply #20 on: December 15, 2018, 06:42:15 am »

Thank you so much and your right. They resemble the Mineral they referred to but you are right my minerals when you look at them closely are much different in composition.

I think they are Black Diamonds.. they are not magnetic ….is Corundum this beautiful? I did not see the specimens glimmering nor have the colors mine do.

I do need to find a professional and have them analyzed.

thanks so much and I will let you know what I find.

regards,

Robert
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Debbie K
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« Reply #21 on: December 15, 2018, 07:46:29 am »

Silicon carbide, which is also called carborundum, can really be beautiful. Moissanite, which is a diamond simulant, is silicon carbide, can be natural or man-made.

Silicon carbide has been man-made since about 1891. It is true that it could have been a curiosity then and that your girlfriends g-grandfather may have thought it was so unusual he would have bothered putting it in a tin and preserving it.

SC is very hard; a 9 on the Mohs hardness scale. Diamond is a 10, as is carbonado. Your thermal tester went past diamond; this is why you need someone to look at it. When you do take it to someone, make sure that they have a tester that will differentiate between Moissanite and Diamond; some don't.

Moissanite has a SG of 3.218–3.22, which is lighter than carbonado. This would probably be the easiest way to make a determination.

Debbie K
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rob71
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« Reply #22 on: December 15, 2018, 08:25:42 am »

Debbie thank you for your links and expertise on minerals.. it shows me how little I actually know about Gems and Diamonds and Minerals.

I appreciate the Links and advice .,.. he did put it in a tin and label it .. it was in a little pouch that is built into the Desk I would not say hidden but secured rather.

his name was Byron O Noyes


I googled his name and it came up with an article lol , https://thecounty.me/2017/05/12/living/from-our-files/ar-lookingback-19-17/

He was well known in the area as quite a Watch Maker.
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