Dec.20 to 22:SAN DIEGO, CALIFORNIA: Wholesale and retail show; Gem Faire Inc.; Scottish Rite Center; Fri. 12-6, Sat. 10-6, Sun. 10-5;
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Sun Dec 15, 2019 10:13 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 12 posts ] 
Author Message
 Post subject: Green spinel - natural or synthetic?
PostPosted: Tue Aug 09, 2016 3:06 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Mon Jun 16, 2014 1:10 pm
Posts: 851
I am shocked!! :shock:

http://www.gia.edu/gems-gemology/summer ... een-spinel

A yellow spinel....on the pic I see a greenish yellow stone...

Never heard of a natural one ( and pale pinkish stones with iron stain is not a yellow spinel)!

_________________
http://www.gemstore-24.com/
gemstones, precision cuts and more...


Last edited by Marlow on Mon Aug 15, 2016 12:47 pm, edited 1 time in total.

Top
 Profile  
Reply with quote  
 Post subject: Re: Yellowish green Spinel
PostPosted: Thu Aug 11, 2016 8:46 am 
Offline
Valued Contributor

Joined: Fri Nov 01, 2013 9:16 am
Posts: 204
Location: Germany
ever saw a green one?

bought from a collector with certificate which states as natural spinel.
Color is (for me) to good to be true. If natural - a very interesting stone...


Attachments:
S100507_spinel.jpg
S100507_spinel.jpg [ 131.46 KiB | Viewed 1991 times ]

_________________
http://www.gemstore-24.com
gemstones, precision cuts and more...
Top
 Profile  
Reply with quote  
 Post subject: Re: Yellowish green Spinel
PostPosted: Thu Aug 11, 2016 11:10 am 
Offline
Gemology Online Veteran
User avatar

Joined: Mon Jun 16, 2014 1:10 pm
Posts: 851
arglthesheep wrote:
ever saw a green one?

bought from a collector with certificate which states as natural spinel.
Color is (for me) to good to be true. If natural - a very interesting stone...


I want to ad that we checked the stone - it is spinel, not Gahnite or Gahnospinel ( RI is in the range of natural spinel - or some newer synthetic). Eyeclean - no diagnostic inclusions.

We know that this color was used to imitate Turmalin.

But there is a Gem report??? So many "???"

Barbra - maybe it would be better to move this to "CSI".

_________________
http://www.gemstore-24.com/
gemstones, precision cuts and more...


Top
 Profile  
Reply with quote  
 Post subject: Re: Yellowish green Spinel
PostPosted: Fri Aug 12, 2016 1:02 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 19948
Location: San Francisco
Done


Top
 Profile  
Reply with quote  
 Post subject: Re: Green spinel - natural or synthetic?
PostPosted: Sat Aug 27, 2016 5:51 pm 
Offline
Site Admin
User avatar

Joined: Fri May 12, 2006 11:24 am
Posts: 7504
Location: Rome, Italy
Nat VS Synth spinel is a piece of cake by PL spectrum, the GIA article mentioned above reports a nice & diagnostic spectrum of the featured stone....

_________________
GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


Top
 Profile  
Reply with quote  
 Post subject: Re: Green spinel - natural or synthetic?
PostPosted: Fri Sep 02, 2016 12:37 pm 
Offline
Valued Contributor

Joined: Fri Nov 01, 2013 9:16 am
Posts: 204
Location: Germany
So I verfied the Gemreport at the lab. It is authentic as they replied.
Also I tested the spectrum of the stone.
As you can see the Fe-Line is visible at 458 nm.

So it seems to be a natural green spinel as I suppose....


Attachments:
Clipboard04.jpg
Clipboard04.jpg [ 47.86 KiB | Viewed 1810 times ]

_________________
http://www.gemstore-24.com
gemstones, precision cuts and more...
Top
 Profile  
Reply with quote  
 Post subject: Re: Green spinel - natural or synthetic?
PostPosted: Sat Sep 03, 2016 4:56 pm 
Offline
Gold Member

Joined: Wed Jan 23, 2013 5:29 pm
Posts: 1027
Location: Paris
Very interesting !
How big is the stone ?


Top
 Profile  
Reply with quote  
 Post subject: Re: Green spinel - natural or synthetic?
PostPosted: Sat Sep 03, 2016 5:19 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Mon Jun 16, 2014 1:10 pm
Posts: 851
Isi wrote:
Very interesting !
How big is the stone ?


0,52 ct - EY ( IF ?) - unfortunately no diagnostic inclusion...

_________________
http://www.gemstore-24.com/
gemstones, precision cuts and more...


Top
 Profile  
Reply with quote  
 Post subject: Re: Green spinel - natural or synthetic?
PostPosted: Sat Sep 03, 2016 5:21 pm 
Offline
Gold Member

Joined: Wed Jan 23, 2013 5:29 pm
Posts: 1027
Location: Paris
What is the refractive index ?
Any strain under crossed polarizers ?


Top
 Profile  
Reply with quote  
 Post subject: Re: Green spinel - natural or synthetic?
PostPosted: Tue Sep 06, 2016 5:52 am 
Offline
Gemology Online Veteran
User avatar

Joined: Mon Jun 16, 2014 1:10 pm
Posts: 851
I hope, arglthesheep can answer your question.

_________________
http://www.gemstore-24.com/
gemstones, precision cuts and more...


Top
 Profile  
Reply with quote  
 Post subject: Re: Green spinel - natural or synthetic?
PostPosted: Tue Sep 06, 2016 10:45 am 
Offline
Valued Contributor

Joined: Fri Nov 01, 2013 9:16 am
Posts: 204
Location: Germany
Hi Isi,
will try to check it today evening. I thought I tested it already and RI-Reading was around 1.718, but I am not sure as I have the stone already a while. Will check also with polarizers...

_________________
http://www.gemstore-24.com
gemstones, precision cuts and more...


Top
 Profile  
Reply with quote  
 Post subject: Re: Green spinel - natural or synthetic?
PostPosted: Tue Sep 06, 2016 11:33 am 
Offline
Gold Member

Joined: Wed Jan 23, 2013 5:29 pm
Posts: 1027
Location: Paris
1.718 is consistent with a natural. Thanks.
Another five-legged mutton you have found !


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 posts ] 

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