Rivista Italiana di Gemmologia #2: Available NOW in English - September 2017; See Gemological Articles below for full details!
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PostPosted: Wed Apr 23, 2008 3:00 pm 
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Hi Wolf,

I want to add step no. 5: Be willing to present your thesis in front of an informed audience and answer their questions in public.

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PostPosted: Wed Apr 23, 2008 3:20 pm 
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For those of you who haven't read this yet, Here is JTV's account of what has happened.
According to them, their discovery of the Mongolian/Chinese source that is reputedly "heat treating" this material, has never been purchased or offered and sold by them as of yet. At least not purchased directly by them through that source.

JTV represents themselves as being purchasers from vendors who are selling this material as natural untreated material. This is the same claims made by others that have bought large quantities from vendors for resale.

Their claims of submitted specimens to Gem Labs for ID may be true. The Identification of the submitted material may be true. Mistakes were made by taking a small sampling for identification and then painting and entire inventory as representative of those findings. An inventory that may have been purchased at different times from different vendors and assuming that COLOR was the only value prerequisite for appropriate marketing representation.

They goofed because of the cost involved with testing every stone individually. The level of testing required by their request may have been minimal as well.

We know by past discussions, that when it comes to Lab testing, you only get what you pay for, especially when it's on a gem with no known treatments.

Assumptions can be made and it can turn out to be quite embarrassing for both the submitter and the Lab, after the fact.
You probably don't hear about all of the BE treatments that were missed by the Labs when this was first discovered and then intensely investigated. And this (corundum) was a gemstone that was known already to be commonly treated.

I think right now, everyone is trying to save face on this, including any Labs that may have been involved with testing this material up to this point.
As with the BE treatment scenario, we may soon be able to distinguish any treated from non treated material. But due to the complexity of the nature of the material, it's chemical composition, the type or types of treatments possibly applied, methods and degree of treatment....well, this is very time intensive and requires a lot of cooperation from various Labs, vendors and maybe even the treaters as well.

It sure is fun to debate, but, I wouldn't have a lynching party just yet. It may require a larger scaffold than what you need for the JTV gang.

Hey, it's the gemstone industry. People lie, cheat, swindle and turn heads at every level. Sometimes, it's a comedy of errors.


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 Post subject: Feldspars
PostPosted: Wed Apr 23, 2008 3:45 pm 
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The feldspar mineral group(s) include three types based on their structure and chemistry.

Orthoclase - a Potassium Aluminum Silicate (monoclinic)

Microcline - a Potassium aluminum silicate (triclinic)
Anorthosclase - Potassium, Sodium Aluminum Silicate (triclinic)

(this is known as the Plagioclase series)
Albite - Potassium Aluminum silicate (triclinic) Na 100-90%
Oligoclase - Na 70-90% remainder Ca
Andesine - Na 50 - 70% remainder Ca
Labradorite - Na 30 -50% remainder Ca
Bytownite - Na 10 -30% remainder Ca
Anorthite -Calcium Aluminum Silicate (triclinic) Na 0 -10%

The Plagioclsse series is an isomorphic series - meaning they share the same general structure, but their physical properties differ depending on their chemistry. This series is much like the various garnet series and their changing chemistry.

It is unlikely in the natural state that either of the two end members has ever been found with their 100% purity. It would take a laboratory with analytical reagents to make either one.

Andesine and Labradorite share a boundary at 50%. So if you found a stone with exactly 50% Na it would be neither or both! Andesine is often found in ROCKS called andesite. They are half way between rhyolitic extrusive lavas and basaltic extrusive lavas. It may also occur in intrusive magma between granite and peridotite. About the range of diorite.

Labradorite tends to occur in intrusive gabbro and extrusive basalts. It is more mafic (containing Ca)

If you want to know which mineral you are likely dealing with, then look at the surrounding geology. Otherwise you will need a chemical analysis to be positive of any material near the 50% boundary.

Check out my site for further info on "rocks" & their chemistry:
http://www.theimage.com/geology/notes4/index8.html

In my experience most gemstones have lost their lines of origin once they are cut. Not true of at least most of the Oregon sunstone. I have not heard of specific locale information for the "African" andesine (but it may well exist). Look at the surroudnding geology. Identify some associated minerals from the site(s), see which of the feldspars they support.

As far as "color" is concerned, the presence of Fe (iron) outside of included iron (hematite, goethite, etc) would be unexpected. The copper in the Oregon material is not in the structure, but rather in inclusions. It doesn't take much to separate the chemistry of the inclusions, iron and copper can be separated spectroscopy wise very easily.

Now I am not an expert in "dyed gems" and don't claim to be. But I can run some simple tests to prove (at least to myself) whether or not a gem has been "tampered with" or is man-made in many cases. See my page on Crab Fire Agate ...

http://www.theimage.com/newgems/synthetic/synthetic12.html

Obviously a piece of pressed glass. How can a pattern on a stone only appear on a finished surface unless the stone grew that way? Any texture or coloration that appears at or near a LAPIDARY surface or boundary, and no where else, is likely a tampered with surface. If the change appears along fractures or inclusions, then maybe it is natural or maybe not. But if it appears only on manipulated boundaries or surfaces, then something is wrong.

Now to call something Andesine or Labradorite, since they share a 50% boundary its a hard call at or near the meet point. It takes a chemistry NOT gemology to make this call. You may be able to separate andesine and labradorite using purely physical methods when they have sufficiently different chemistries, but not near the meet point!

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 Post subject:
PostPosted: Wed Apr 23, 2008 4:33 pm 
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Well look, everyone involved in this has their own story, good or bad, that best serves their own interest.

Too much of their interest may be dependant on what they have been told by others and now they're in the precarious position of defending themselves and their investments.

I'm going to try and look at every side of this until rock solid determinations have been made. Some of this, such as Origin may have to be taken on faith if they can't even find the damn mine, and it is no longer producing. No mine, no geology. Freakish things happen in the earths crust.

I'm just happy to be a part of complicating things further. :)


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 Post subject:
PostPosted: Wed Apr 23, 2008 5:06 pm 
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I seem to remember a scientist soaking a piece of clamped space shuttle-gasket material in ice-water durring the investigation of a "major malfunction"; thereby demolishing the arguments of the people who were saying the gasket material wouldn't be affected by cold. Sometimes simple tests are appropriate. As for diffusion treated stones, immersion is still a recommended test.

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 Post subject:
PostPosted: Wed Apr 23, 2008 5:12 pm 
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ehm... space temp is just about -270 degrees celcius. Icewater is 0 degrees celcius. I don't get the 'thereby demolishing the arguments of the people who were saying the gasket material wouldn't be affected by cold' part. I hold up pretty well at 0 Celcius but I'm afraid I'll freeze instantly at -270. I can relate to the gasket ;)


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 Post subject:
PostPosted: Wed Apr 23, 2008 5:49 pm 
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guess you didn't see the news cast after the Challenger desaster. It was some years ago.

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 Post subject:
PostPosted: Wed Apr 23, 2008 7:02 pm 
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Okay guys, I got some pics of my red and green andesines/labradorities. Hopefully I did the immersion cell test correctly (it was my first time). I apologize in advance for the graininess of the photos...I'm sure my camera can take clearer images, but I haven't yet figured out how. :?

The RED: (which is actually more of an orangey-red)

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AND THE BLUE-GREEN:

Image
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I did not see any color concentrations at all in the facet junctions. Not even a trace.

Obviously the red stone has some strong zoning.

Both gems looked like the pictures I've seen of sunstone rough: color on the INSIDE, but colorLESS on the outside.

The black specs on the green stone are air bubbles.

I don't know if these pictures will tell you guys anything...but have fun speculating. :)

(And for those who are interested, these stones were purchased from JTV in 2005.) :D

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 Post subject:
PostPosted: Wed Apr 23, 2008 7:16 pm 
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Thank you Gem Junkie for taking the time to prepare that presentation.
I currently have 4 cut andesine/labradorite stones and they ALL look like yours with immersion.
I see no concentrations of color on facet junctions, but there is definite color zoning....just like we have seen in the rough samples.


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 Post subject:
PostPosted: Wed Apr 23, 2008 7:23 pm 
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Does this mean there is no :smt106 party yet?

What am I going to do with all of these chips and pretzels?


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 Post subject:
PostPosted: Wed Apr 23, 2008 7:42 pm 
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Save it til I get back with the beer :lol:


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 Post subject:
PostPosted: Wed Apr 23, 2008 7:47 pm 
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Rum please. :)


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 Post subject:
PostPosted: Wed Apr 23, 2008 8:09 pm 
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Diffuse them by tumbling in Guacamole. :lol:

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 Post subject: Guacamole
PostPosted: Wed Apr 23, 2008 8:13 pm 
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Noooo save the Guacamole for the chips' I think we're gonna be in trouble. :roll: Sorry Barbra


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 Post subject:
PostPosted: Wed Apr 23, 2008 8:34 pm 
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Add six more to the total that look just like the above. All six were orange red to red with no concentration on the facet edges. All were purchased below $12 per ct and four were purchased from Thaigem. The other two from Multicolour. All six came thru Thailand. Neither claimed to know where they originated from at the time of purchase. But they are not from Oregon.
I hate to say it, but no one seems to be able to find one like the ISG gems.


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