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 Post subject: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 11:00 am 
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Lang Antiques recently purchased a remarkable diamond, we have all had the pleasure of studying:

4.32 carats, emerald-cut.

We sent it to the GIA for grading, and it returned D Flawless.
Upon further investigation, the GIA determined it to be type IIb.

The stone does NOT fluoresce with long or short wave UV.
BUT, after exposing it to 30 seconds of SWUV, it phosphoresces for several minutes.

Here is a shot of the phosphorescence seen in normal light:
Image

And here, when viewed in a dark closet.
Image

IIb diamonds are electrically conductive, therefore, it tests as moissanite on the diamond tester.
cool......awesome, cool.


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 Post subject: Re: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 11:16 am 
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Thats the one discussed in Gem-A mailing list.
Heard it was for sale... :) Not my cup of tea though and it will probably not suit my wallet either :)

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 11:22 am 
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Wow, cool indeed :D

To be honest I didn't know type IIb can be colorless D.

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does NOT fluoresce with long or short wave UV


I'm curious about your observations. Basically you are saying phosphorescence didn't show up as fluorescence until source was switched off. Was it perhaps masked by slight visible glow from the UV source?

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 11:29 am 
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Apparently when the quantity of boron in a type IIb is minimal, a colorless diamond can be produced.
Most IIb diamonds are blue or blue/gray :like the Hope Diamond which phosporesces red.

And, the lack of fluorescence is something that astounded me as well.
It is not only our opinion, but the GIA called it : fluorescence:inert


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 Post subject: Re: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 11:55 am 
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While I usually don't care about nor like diamonds... Who can not love this one! That is awesome!

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 12:25 pm 
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Ooohhh, it's fantastic. Love the phosphorescence! :shock: :mrgreen:

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 4:51 pm 
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Wowser!!! :shock: Wish my wallet was thicker, too!

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 9:08 pm 
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Way cool. Also didn't know that they could be D color. On another note, how many diamonds do this? I doubt very few are put under swulv for any length of time over a second or two, if at all. Anything that would tip you off?

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Fri Oct 21, 2011 10:41 pm 
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We tested for phosphorescence after learning the diamond was Type IIb.
Typical characteristics of Type IIb are cross-hatched “tatami” strain pattern, transparent to short-wave UV, electrical conductivity AND blue or red phosphorescence.
So, of course, we tested for everything.

Type IIb diamonds account for ~0.1% of gem diamonds and as I'm sure you all know, are usually a steely blue or gray due to boron atoms scattered within the crystal matrix. A colorless IIb is super rare, but not unheard of.

Although one can not conclusively determine origin of diamonds by type, Type IIb diamonds are less widely distributed than others; most come from India and the Cullinan (formerly Premier) mine in South Africa (King et al., 1998; G&G Summer 2009 "THE “TYPE” CLASSIFICATION SYSTEM OF DIAMONDS AND ITS IMPORTANCE IN GEMOLOGY").

We have some more photos of the diamond coming soon...some real good ones. 8)


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 Post subject: Re: D Flawless, Type IIb
PostPosted: Sun Oct 23, 2011 12:06 pm 
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very impressing Barbra, thank you for sharing.

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Mon Oct 24, 2011 8:52 am 
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Swishman wrote:
While I usually don't care about nor like diamonds... Who can not love this one! That is awesome!


Agree! :)


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 Post subject: Re: D Flawless, Type IIb
PostPosted: Mon Oct 24, 2011 11:34 am 
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what can i say.......WOW!!!

Barbra Voltaire wrote:
We have some more photos of the diamond coming soon...some real good ones. 8)


geesh, can't wait to see'em!! 8) :D

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Mon Oct 24, 2011 6:52 pm 
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For me Diamonds were just colorless stones with a high dispersionuntil now. But this one ....

:shock:

Thanks for sharing Mrs. B. , the possibility of getting one of these under your loupe is once in a lifetime.

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 Post subject: Re: D Flawless, Type IIb
PostPosted: Mon Oct 31, 2011 7:21 pm 
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Very nice, thanks for sharing.


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 Post subject: Re: D Flawless, Type IIb
PostPosted: Tue Nov 01, 2011 12:24 pm 
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A couple updates.
Here is the diamond under normal conditions, just sitting around:
Image

Here, after 30 seconds of SWUV, in the closet, the diamond displays luminescence for SEVERAL minutes:
Image


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