FCD - Undetermined origin for a blue?

[kroshka]

Something interesting that I just came across that I don't think I have ever encountered before - a fancy grayish blue diamond that has a GIA report stating that the color origin is "undetermined". I've only ever seen this for green fcd's.

http://www.ebay.com/itm/GIA-1-00-Ct-RARE-Fancy-Graysih-Blue-Square-Mod-Brilliant-Natural-Diamond-/310873331311?pt=Loose_Diamonds&hash=item48617e966f





Kroshka

 

[LoversKites]

How unusual! How would a vendor go about pricing something like this?

 

[kroshka]

I would assume price has to be lower than a comparable stone that has a GIA report stating a stone's color origin is natural. Here is what I think kind of stinks about what the seller wrote - see red arrow.



Kroshka

 

[kroshka]

The same ebay seller has other blue's with GIA reports that are also undetermined for origin of color. For reference:

http://www.ebay.com/itm/GIA-1-03-Ct-RARE-Fancy-Light-Greenish-Blue-Round-Brilliant-Cut-Natural-Diamond-/310873334949?pt=Loose_Diamonds&hash=item48617ea4a5

http://www.ebay.com/itm/GIA-1-75-Ct-RARE-Fancy-Light-Gray-Blue-Round-Brilliant-Cut-Natural-Diamond-/151231409069?pt=Loose_Diamonds&hash=item2336182bad

http://www.ebay.com/itm/GIA-1-05-Ct-Fancy-Light-Greenish-Blue-Square-Mod-Brilliant-Natural-Diamond-/151231421531?pt=Loose_Diamonds&hash=item2336185c5b

http://www.ebay.com/itm/GIA-1-09-Ct-Fancy-Light-Greenish-Blue-Square-Mod-Brilliant-Natural-Diamond-/310873325390?pt=Loose_Diamonds&hash=item48617e7f4e

http://www.ebay.com/itm/GIA-1-00-Ct-Fancy-Light-Greenish-Blue-Rectangular-Mod-Brilliant-Natural-Diamond-/310873336395?pt=Loose_Diamonds&hash=item48617eaa4b

Kroshka

 

[Marlow]

I love these ebay stores from Thailand - demantoid and alexandrite is always from Russia and diamonds are natural and untreated .....

the clarity is NOT SI 2 - you will see the black inclusions with the naked eye. No exact clarity and orign of color and 25000$ - perfect deal!

I don't understand why GIA is not able to say whether this stone is treated or not.

 

[chrono]

The larger reputable labs prefer to play it safe. They are not going to state on paper that the colour origin is natural unless they are 100% sure of it. If there is any doubt, then it will be inconclusive.

 

[Marlow]

This would be an interesting discussion on Gemologyonline forum too.

 

[Marlow]

@Chrono

Was a rhetorical question.

Six or more blue Diamond with 1 carat and more??? Very unusual.

The Ia diamonds with high hydrogen content ( the deep to dark gray violet/blue stones from Argyle Mine) or IIb with boron content are OR can be blue - this should be no problem in my opinion for a lab.

Hope they start some research.

 

[chrono]

@Chrono
Was a rhetorical question.

Six or more blue Diamond with 1 carat and more??? Very unusual.

The Ia diamonds with high hydrogen content ( the deep to dark gray violet/blue stones from Argyle Mine) or IIb with boron content are OR can be blue - this should be no problem in my opinion for a lab.

Hope they start some research.

Gotcha! I'm guessing that perhaps GIA found traces of irradiation and thus could not determine whether it happened naturally or otherwise. I'm sure that GIA did not look to see all these other stones on eBay and do not know which FCD sent to them are from eBay, hence the caution.

 

[Marlow]

Maybe the vendor did not allow some more research....

I think they are treated - of course only my opinion.

But I am shocked - diamond is now really a problem - CVD coated topas, synthetic diamond, HPHT and .....

 

[chrono]

Maybe the vendor did not allow some more research....
I think they are treated - of course only my opinion.

But I am shocked - diamond is now really a problem - CVD coated topas, synthetic diamond, HPHT and .....

I agree; if not, then naturally coloured blue FCDs are far more common than we are led to believe.

 

[Marlow]

On the other hand it is easier to find a blue diamond then a REAL nice vanadium chrysoberyl.

 

[T L]

@Chrono
Was a rhetorical question.

Six or more blue Diamond with 1 carat and more??? Very unusual.

The Ia diamonds with high hydrogen content ( the deep to dark gray violet/blue stones from Argyle Mine) or IIb with boron content are OR can be blue - this should be no problem in my opinion for a lab.

Hope they start some research.

Gotcha! I'm guessing that perhaps GIA found traces of irradiation and thus could not determine whether it happened naturally or otherwise. I'm sure that GIA did not look to see all these other stones on eBay and do not know which FCD sent to them are from eBay, hence the caution.

That's probably the case. I do know that many green diamonds are of undetermined color origin because of the fact that natural and artificial irradiation look identical to the instruments that detect them. For example, many green diamonds are determined natural in color before they are cut. It's pretty scary when spending thousands of dollars on gems that have a color that might not be traceable back to the time they came out of the ground. I would avoid such diamonds, unless you can unequivocally know that the irradiation is natural.

Some blue diamonds attribute their color to trace elements however, which is more easily deemed natural in color. They use similar trace elements in the creation of synthetic diamonds, but the growth lines of these diamonds are easily detected with special equipment.

 

[Marlow]

Maybe this is interesting:

http://www.gemologyonline.com/Forum/phpBB2/viewtopic.php?f=7&t=14961

Natural green diamond vs irradiated

GIA should start to add the type of a natural diamond in a certificate - Natural Diamond Typ II b for example.

 

[kroshka]

Maybe this is interesting:

http://www.gemologyonline.com/Forum/phpBB2/viewtopic.php?f=7&t=14961

Natural green diamond vs irradiated

GIA should start to add the type of a natural diamond in a certificate - Natural Diamond Typ II b for example.

Interesting you brought this point up, as I have a stone I meant to post more about but never really got around to actually doing it. I have an EGL USA report stating the stone's color is of natural origin and a GIA report stating the color as undetermined. I realize GIA is the most reputable in terms of color origin for FCD's, however, it still makes for an interesting discussion. Will try to dig up the reports to get them scanned so I can post.

Kroshka

 

[kroshka]

Ok, here are copies of the reports. I'd appreciate any discussion on this as I kind of considered this a bit of a case study stone.




Kroshka

 

[kroshka]

And, I know great photos mean a lot, but all I could gather at this moment were a few crappy phone photos, cause I know y'all would be curious what the stone sort of looks like.





Kroshka

 

[Marlow]

Yes - that would be interesting.

A useful tool is a SWUV Spotter - not cheap and you need a short wave UV lamp ( But you can build the spotter... not difficult and cheap).

Typ I diamond absorbe SWUV - Typ II let it pass. HPHT Diamond are Type IIa ( only a small amount among diamonds but theycan be used
to produce colorless diamond from brown for example).

The spotter is a tube with a small window at one end - and a coated part that flouresces green ( if you build it you can use a piece of scheelite) . At the other end is a hole where you fix the diamond with plasteline - important is that the SWUV only pass the diamond!!

If the coated part or scheelite start to flouresces it is a Type II ( a or b ) - if not Type I (a or b).

This is def. a standard test in a lab - quick and easy!!

 

[kroshka]

Yes - that would be interesting.

A useful tool is a SWUV Spotter - not cheap and you need a short wave UV lamp ( But you can build the spotter... not difficult and cheap).

Typ I diamond absorbe SWUV - Typ II let it pass. HPHT Diamond are Type IIa ( only a small amount among diamonds but theycan be used
to produce colorless diamond from brown for example).

The spotter is a tube with a small window at one end - and a coated part that flouresces green ( if you build it you can use a piece of scheelite) . At the other end is a hole where you fix the diamond with plasteline - important is that the SWUV only pass the diamond!!

If the coated part or scheelite start to flouresces it is a Type II ( a or b ) - if not Type I (a or b).

This is def. a standard test in a lab - quick and easy!!

Hmm unfortunately I don't have the equipment, are there specific instructions or a website you could post that has info on where I could get the materials to build a cheap spotter?

Kroshka

 

[Marlow]

I will post some links tomorrow ( it is 11:18 pm here)

http://www.gia.edu/cs/Satellite?blobcol=gfile&blobheader=application%2Fpdf&blobheadername1=Content-Disposition&blobheadername2=MDT-Type&blobheadername3=Content-Type&blobheadervalue1=attachment%3B+filename%3DThe-“Type”-Classification-System-of-Diamonds.pdf&blobheadervalue2=abinary%3B+charset%3DUTF-8&blobheadervalue3=application%2Fpdf&blobkey=id&blobtable=GIA_DocumentFile&blobwhere=1355958143608&ssbinary=true

VERY INTERESTING

Check Gemology online - there are some very nice people ( scientist, trade ...) - post your pics and the two reports. They will like to discuss this stone

The stone is very interesting and beautiful - same problem - a very light color, a mix of blue and green. I hope the color is natural!!!!

I try to find with "defect" or color center the two peaks in the spectrum from EGL Certificate are.

Maybe GIA report was not the complete programm.

Bye