August 31-September3—RALEIGH, NORTH CAROLINA: Annual show; Treasures of the Earth, Inc.; NC State Fairgrounds; Fri. 12-6, Sat. 10-5, Sun. 10-5, Mon. 10-4;
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Wed Aug 15, 2018 1:01 am

All times are UTC - 4 hours




Post new topic Reply to topic  [ 16 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Synthetic and real Sapphire
PostPosted: Thu Oct 14, 2010 5:15 am 
Offline
Established Member

Joined: Sun Sep 26, 2010 11:01 pm
Posts: 46
Hi Guys,

Is there any different in the raman spectrum of synthetic and real sapphire? Or can we notice any different with FTIR or UV-VIS-NIR spectroscopy? I have attached 2 raman spectra of sapphire and shell. Would appreciate if any of you can give me some comments. Thanks!


Best Regards,
Zen


Attachments:
File comment: Shell
Picture12.tif
Picture12.tif [ 156.72 KiB | Viewed 6358 times ]
File comment: sapphire
Picture11.tif
Picture11.tif [ 158.63 KiB | Viewed 6358 times ]
Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Thu Oct 14, 2010 9:24 am 
Offline
Site Admin
User avatar

Joined: Fri May 12, 2006 11:24 am
Posts: 7488
Location: Rome, Italy
Hi Zen,

i'm not able to see your pics, i'm the only one? :roll:
ciao
alberto

_________________
GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Thu Oct 14, 2010 9:48 am 
Alberto wrote:
Hi Zen,

i'm not able to see your pics, i'm the only one? :roll:
ciao
alberto


No. I can't either. But it seems that several others have viewed them. This occasionally seems to happen. Don't know why but wonder about the method of attachment??


Top
  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Thu Oct 14, 2010 10:12 am 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 18874
Location: San Francisco
I don't see them either.


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Thu Oct 14, 2010 10:13 am 
Offline
Gemology Online Royal Princess

Joined: Mon Oct 17, 2005 10:56 am
Posts: 6460
Location: The frozen north prairie :-/
Nor I (not that I could help much anyway :P ).

_________________
ISG Registered Gemologist
GIA Graduate Gemologist

barbaraellisdesigns.com


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Thu Oct 14, 2010 9:10 pm 
Offline
Established Member

Joined: Sun Sep 26, 2010 11:01 pm
Posts: 46
Attachment:
Picture11.JPG
Picture11.JPG [ 94.19 KiB | Viewed 6304 times ]
Attachment:
Picture12.JPG
Picture12.JPG [ 94.71 KiB | Viewed 6304 times ]


Sorry, the background og previous pictures are too dark. I think these one are better ..Thanks!


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Fri Oct 15, 2010 3:02 am 
Offline
Site Admin
User avatar

Joined: Fri May 12, 2006 11:24 am
Posts: 7488
Location: Rome, Italy
Hi,

perhaps you could find some infos HERE
ciao
alberto

_________________
GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Sat Oct 16, 2010 1:29 am 
Offline
Established Member

Joined: Sun Sep 26, 2010 11:01 pm
Posts: 46
Dear Alberto,

Thanks for your reply. I found that the spectrum for synthetic and real sapphire are very identical. In your opinion, what is the best way to identify them using spectroscopic method?

THanks!


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Sat Oct 16, 2010 3:08 am 
Offline
Site Admin
User avatar

Joined: Fri May 12, 2006 11:24 am
Posts: 7488
Location: Rome, Italy
zen wrote:
In your opinion, what is the best way to identify them using spectroscopic method?



I can't be of much help on this side cos i don't own a raman spectrometer, hopefully i could have an usable UV-VIS-NIR setup in this lifetime.
However i really don't need BIG guns to solve the synth/nat sapphire issue, brain-microscope-books is the trio i always used and still feel very confortable with them 8)
ciao
alberto

_________________
GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Sat Oct 16, 2010 8:22 am 
zen wrote:
Dear Alberto,

Thanks for your reply. I found that the spectrum for synthetic and real sapphire are very identical. In your opinion, what is the best way to identify them using spectroscopic method?

THanks!


OK, I'm lost....Can we have a little more information here?

1. You present two graphs. One is labelled 'Shell' and the other 'Sapphire'. Does Shell = Synthetic? Or??

2. In each graph, both the intensity of the collected return from the target and the wavenumber (related mathematically to the wavelength of the collected light) are plainly and widely different. In what ways do you see them to be similar?

3. AIUI, Raman spectroscopy is about observing molecular vibration under coherent light bombardment. Since the chemical composition a synthetic and a natural Sapphire is essentially the same, why should you expect Raman spectroscopy to differentiate reliably between the two?

Thanks


Top
  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Sat Oct 16, 2010 10:36 am 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 18874
Location: San Francisco
Alberto wrote:
Hi,

perhaps you could find some infos HERE
ciao
alberto


Wow...that's a helluva resource!


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Sun Oct 17, 2010 8:40 pm 
Offline
Established Member

Joined: Sun Sep 26, 2010 11:01 pm
Posts: 46
Dear Kerensky,

I am sorry that I have appeared not very clear to myself too and causing the confusion. I just got too carried away and was asking multiple questions without explaining more.

1) The first graph is synthetic sapphire and the second one is indeed shell. I did not put the spectrum for the real sapphire.
2) as above
3) I am wondering if those inclusion or impurities might cause some little peaks that can be distinct for us to differentiate any difference? If not do you know of a better way?


Thanks alot!


Regards,
Zen


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Sun Oct 17, 2010 10:58 pm 
zen wrote:
I am sorry that I have appeared not very clear to myself too and causing the confusion....


Hi Zen,

It's OK, All of us do it from time to time :wink:

Quote:
1) The first graph is synthetic sapphire and the second one is indeed shell. I did not put the spectrum for the real sapphire.
2) as above
3) I am wondering if those inclusion or impurities might cause some little peaks that can be distinct for us to differentiate any difference? If not do you know of a better way?


If you use the link Alberto gave you, you will see that your basic idea is correct. Synthetic Sapphire (and Ruby) is commonly is fairly pure and lacks the random selection of impurities that Mother Earth adds to natural gemstones. But you don't need Raman to detect this. Synthetics are made quickly and natural gemstone rather slowly, with the result that there are different microscopic flaws which give visual clues as to whether the stone is natural or synthetic. This is a skilled business, requiring much learning and practice; for some; it becomes a life-time study. A synthesiser can add trace elements to his stuff easily enough but forging in days what took nature thousands of years to make and perhaps alter, break and mend again (as one example) is not really practical. Also, there are often microscopic flaws in the synthetic material that are a give-away for synthetic production.

Forgive me if this makes it seem easy to tell natural from synthetic; it isn't - but it can be done and, it seems, Raman spectroscopy is simply not the best tool for tackling this work. The more flawless a natural gemstone is the more valuable it is - and the closer the chemical composition of the natural and the doctored synthetic can become.

Not sure that's the answer you want to hear but it's the best I can do for you....


Top
  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Tue Oct 19, 2010 5:39 am 
Offline
Established Member

Joined: Sun Sep 26, 2010 11:01 pm
Posts: 46
Dear Kerensky,

Thanks so much for your prompt reply. I really appeciate so much. It been very nice to learn so much from you guys in this forum. I am new in the industry with some materials characterization background. I know the difficulties involve in the identification real/synthetic gemstones, but wish to really try using some kind of spectoscopic methods to characterizate these minerals. Is there any possibibility? Thanks.

Regards,
Zen


Top
 Profile  
Reply with quote  
 Post subject: Re: Synthetic and real Sapphire
PostPosted: Tue Oct 19, 2010 7:16 am 
zen wrote:
Dear Kerensky,

Thanks so much for your prompt reply. I really appeciate so much. It been very nice to learn so much from you guys in this forum. I am new in the industry with some materials characterization background. I know the difficulties involve in the identification real/synthetic gemstones, but wish to really try using some kind of spectoscopic methods to characterizate these minerals. Is there any possibibility? Thanks.

Regards,
Zen


Dear Zen.

I hope that you will stay with this forum, not only to read what others put here but to make some contributions of your own. We are all learners, just at differennt stages along that learning road and the thoughts of others with similar interests are rarely without value - even if one does not always agree with them :roll:

It would be very convenient if one form or another of spectroscopy could differentiate with a high degree of certainty between synthetic and natural Corundum - and also between treated and untreated natural Corundum. Certainly, there are more than a few who actively research such a possibility.

Regards,
Kerensky


Top
  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 16 posts ]  Go to page 1, 2  Next

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock