We use cookies to show content based on your preferences. If you continue to browse you accept their use and installation. More information. >

FMF - Friends of Minerals Forum, discussion and message board
The place to share your mineralogical experiences

FMF English Forum is moderated by John S. White and Peter Megaw
 

Spanish message board






Newest topics and users posts
27 Jun-04:11:14 Re: sainte marie-aux-mines show 2017 (Roger Warin)
27 Jun-01:29:20 Re: genuine aventurine? (Volkmar Stingl)
27 Jun-01:25:53 Re: carlos pareja photo collection (Carlos Pareja)
26 Jun-18:21:05 Re: witherite xls from ky (Pete Richards)
26 Jun-16:32:29 The mizunaka collection - quartz (Am Mizunaka)
26 Jun-16:29:21 Re: witherite xls from ky (Dontgogreen)
26 Jun-16:27:53 Re: witherite xls from ky (Dontgogreen)
26 Jun-16:25:49 Witherite xls from ky (Dontgogreen)
26 Jun-11:36:49 Re: sainte marie-aux-mines show 2017 (Philippe Durand)
26 Jun-11:27:02 Re: sainte marie-aux-mines show 2017 (Philippe Durand)
26 Jun-11:25:01 Re: sainte marie-aux-mines show 2017 (Philippe Durand)
26 Jun-11:21:58 Re: sainte marie-aux-mines show 2017 (Philippe Durand)
26 Jun-09:03:55 Re: genuine aventurine? (Lluis)
26 Jun-06:22:10 Re: the bogota´s french connection (Fiebre Verde)
26 Jun-06:00:20 Re: sainte marie-aux-mines show 2017 (Jordi Fabre)
26 Jun-05:56:09 Re: carlos pareja photo collection (Carlos Pareja)
26 Jun-05:46:58 Re: the bogota´s french connection (Franjungle)
26 Jun-05:39:48 Re: struggling to identify the green mineral (Jordi Fabre)
26 Jun-03:49:50 Re: genuine aventurine? (Evin Likes Rocks)
25 Jun-23:01:43 Re: genuine aventurine? (Volkmar Stingl)
25 Jun-17:29:28 Re: genuine aventurine? (Evin Likes Rocks)
25 Jun-15:26:35 Re: sainte marie-aux-mines show 2017 (Gail)
25 Jun-14:07:06 Re: genuine aventurine? (Lluis)
25 Jun-14:00:10 Re: carlos pareja photo collection (Carlos Pareja)
25 Jun-13:02:35 Re: don lum collection (Don Lum)

For lists of newest topics and postings click here


RSS RSS

View unanswered posts

Why and how to register

Index Index
 FAQFAQ RegisterRegister  Log inLog in
 {Forgotten your password?}Forgotten your password?  

Like
29420


The time now is Jun 27, 2017 05:18

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
Huanggang Mine scheelite color
  
  Index -> Incorrect classification and fakes
Like


View previous topic :: View next topic  
Author Message

Josele




Joined: 10 Apr 2012
Posts: 275
Location: Tarifa, Cádiz


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jul 12, 2014 11:22    Post subject: Huanggang Mine scheelite color  

As seen in http://www.mineral-forum.com/message-board/viewtopic.php?p=40197#40197, scheelite specimens from Huanggang Mine (or, more general, Chifeng Prefecture, Inner Mongolia Autonomous Region, China) are sometimes treated to clean calcite matrix with an unexpected result of a change of scheelite color. In the related thread the color has turned to green. I wonder if my specimen has also been treated, because the brownish color is different to the whitish colors seen in Mindat gallery.
Has anyone seen this brownish color in other scheelite specimens from the Huanggang Mine?



P1020187_2.JPG
 Description:
Scheelite with a bit of feldspar and quartz
Huanggang Fe-Sn deposit (Huanggangliang Mine; Huanggang Mine), Hexigten Banner (Keshiketeng Co.), Ulanhad League (Chifeng Prefecture), Inner Mongolia Autonomous Region, China
6 x 4,5 x 2,5 cm
 Viewed:  9185 Time(s)

P1020187_2.JPG



P1020193_2.JPG
 Description:
Scheelite
Huanggang Fe-Sn deposit (Huanggangliang Mine; Huanggang Mine), Hexigten Banner (Keshiketeng Co.), Ulanhad League (Chifeng Prefecture), Inner Mongolia Autonomous Region, China
6 x 4,5 x 2,5 cm

Here under SW UV
 Viewed:  9181 Time(s)

P1020193_2.JPG



_________________
Josele
Back to top
Reply to topic Reply with quote
Like
   

lluis




Joined: 17 Nov 2006
Posts: 510

View user's profile

Send private message

PostPosted: Jul 12, 2014 11:46    Post subject: Re: Huanggang Mine scheelite color  

Hi, Josele

As far as I remember, I think to have seen several specimens with this colour.
From very respected sellers.

So, I would think that yours is as is.

The green one, besides, has a very soft appearance, with edges that looks as polished to my eyes, not sharp as the ones your specimen has.

Anyway, seen more as yours.

With best wishes

Lluís
Back to top
Reply to topic Reply with quote
Like
   

Jordi Fabre
Overall coordinator of the Forum



Joined: 07 Aug 2006
Posts: 3869
Location: Barcelona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jul 12, 2014 11:53    Post subject: Re: Huanggang Mine scheelite color  

It looks like slightly tinted due the etching process, but not so far of its real color, usually whitish, cream and some times bluish or grey-bluish by the Molybdenite inclusions.

As said in: http://www.mineral-forum.com/message-board/viewtopic.php?p=40197#40197 is easy to know it just cleaning them with super iron out or similar.
Back to top
Reply to topic Reply with quote
Like
   

GneissWare




Joined: 07 Mar 2008
Posts: 1259
Location: California


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jul 12, 2014 11:57    Post subject: Re: Huanggang Mine scheelite color  

I agree. It looks like it needs a soak in Super Iron Out. It should go more grey.
Back to top
Reply to topic Reply with quote
Like
   

lluis




Joined: 17 Nov 2006
Posts: 510

View user's profile

Send private message

PostPosted: Jul 12, 2014 12:46    Post subject: Re: Huanggang Mine scheelite color  

By the way, I have seen in page placed by Josele that some are pinkish/violet.

Anyone knows reason?

With best wishes

Lluís
Back to top
Reply to topic Reply with quote
Like
   

Jordi Fabre
Overall coordinator of the Forum



Joined: 07 Aug 2006
Posts: 3869
Location: Barcelona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jul 12, 2014 13:45    Post subject: Re: Huanggang Mine scheelite color  

lluis wrote:
By the way, I have seen in page placed by Josele that some are pinkish/violet.

True! I forgot the very scarce violet Scheelites from Huanggang (not really pinkish natural color). Some from there has this natural color but I don't know why (maybe no reason, just color centers).

In fact in the past in Tae Hwa Mine, South Korea they also found violet Scheelites, see below.



Scheelite with Quartz and Dolomite - Tae Wha Mine_Neungam-ri_Chungju_Chungcheongbukdo_South Korea copia.jpg
 Description:
Scheelite with Quartz and Dolomite
Tae Wha Mine, Neungam-ri, Chungju, Chungcheongbukdo, South Korea
Specimen size: 5.5 × 3.7 × 3.4 cm
Main crystal size: 3.6 × 3.5 cm
Former collection of Folch duplicates
Photo: Reference Specimens
 Viewed:  9092 Time(s)

Scheelite with Quartz and Dolomite - Tae Wha Mine_Neungam-ri_Chungju_Chungcheongbukdo_South Korea copia.jpg


Back to top
Reply to topic Reply with quote
Like
   

Josele




Joined: 10 Apr 2012
Posts: 275
Location: Tarifa, Cádiz


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jul 12, 2014 14:42    Post subject: Re: Huanggang Mine scheelite color  

In the reverse of this specimen can see a colorless core. I guess this a sign that it is not treated but anyway next monday I will buy any stain remover similar to Super Iron Out, which is not available in Spain.
Thanks to all for your help, on monday I will post the result after cleaning.



P1130630.JPG
 Description:
Scheelite
Huanggang Fe-Sn deposit (Huanggangliang Mine; Huanggang Mine), Hexigten Banner (Keshiketeng Co.), Ulanhad League (Chifeng Prefecture), Inner Mongolia Autonomous Region, China
6 x 4,5 x 2,5 cm

Reverse side
 Viewed:  9117 Time(s)

P1130630.JPG



_________________
Josele
Back to top
Reply to topic Reply with quote
Like
   

lluis




Joined: 17 Nov 2006
Posts: 510

View user's profile

Send private message

PostPosted: Jul 12, 2014 15:21    Post subject: Re: Huanggang Mine scheelite color  

Hi, Jordi, Josele

I agree with the iron stained reason for Josele brownish color (for the piece, I mean).
I would try with Waller's solution, that is non acidic, or if you are in a hurry, with oxalic acid (cold solution!)
Anyway, I have searched, and scheelite dissolves in hot acid, so the green in some damages seems to be due to acid treatement, and non exactly in cold.... or room temperature.

For violet colour, I doubt in color centers (which are in the pink fluorites). I would think in a manganese maybe wolframate... (but with this colour, should be a Mn3+, that is not the most and stable thing.....Anyway, found in Rodhos, so....)

Pity that there is no study (pity for me, mainly; I doubt it would increase our knowledge too much, but.... :-) )

Many thanks!

Lluís
Back to top
Reply to topic Reply with quote
Like
   

Jordi Fabre
Overall coordinator of the Forum



Joined: 07 Aug 2006
Posts: 3869
Location: Barcelona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jul 12, 2014 15:48    Post subject: Re: Huanggang Mine scheelite color  

lluis wrote:
...For violet colour, I doubt in color centers (which are in the pink fluorites). I would think in a manganese maybe wolframate... (but with this colour, should be a Mn3+, that is not the most and stable thing.....Anyway, found in Rodhos, so....)...

The last studies about the color in minerals seem to disprove the old theory of the metal Ions giving the color. We'll see...
Back to top
Reply to topic Reply with quote
Like
   

lluis




Joined: 17 Nov 2006
Posts: 510

View user's profile

Send private message

PostPosted: Jul 13, 2014 01:16    Post subject: Re: Huanggang Mine scheelite color  

Hi, Jordi

We had already had a talk (I think two years ago) on that.
That there is a part of color that is due to color centers, agreed (like the pink fluorites).
But all due to color center (except if there is a new definition, and all (cations, charge tranference, voids, distortions in net and all) are considered "centers of color), well... I would like to see the theory.

Anyway, a funky theory that the Greeks knew how to plate lead with a copper salt first and a silver salt later, or that the Romans could do electroplated tin denarii, had been in vogue. The first defended by at least some archaeologists, and referring to a fake slipped inside an Iitalian hoard of silver coins (the Parabita hoard; found and unrecorded properly I think at the beginning of 20th century or end of 19th century in Italia)

Anyway, we will see...

With best wishes

Lluís
Back to top
Reply to topic Reply with quote
Like
   

Josele




Joined: 10 Apr 2012
Posts: 275
Location: Tarifa, Cádiz


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jul 21, 2014 13:25    Post subject: Re: Huanggang Mine scheelite color  

Just to comment that finally I have decided to leave my scheelite specimen as it is.

As Super Iron Out is not available in Spain and even less in my small village, I found Dr Beckmann stain remover special for iron oxide, which I suppose is somewhat similar to SIO. But when I was ready to use it, I was thinking that if the brown color comes from iron oxide, it must be natural, so it is better to leave it like this. After all it's a nice honey color...



0725105001325899353.jpg
 Description:
Scheelite + Muscovite
Mt Xuebaoding, Pingwu Co., Mianyang Prefecture, Sichuan Province, China
7 x 5 x 4 cm
Honey brown color is a common color for scheelite and there is no reason to think it is dyed or altered.
 Viewed:  8589 Time(s)

0725105001325899353.jpg



_________________
Josele
Back to top
Reply to topic Reply with quote
Like
   

GneissWare




Joined: 07 Mar 2008
Posts: 1259
Location: California


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jul 21, 2014 17:48    Post subject: Re: Huanggang Mine scheelite color  

This is pretty typical color for Xuebaoding, and it already looks like it has been properly cleaned.
Back to top
Reply to topic Reply with quote
Like
   
Display posts from previous:   
   Index -> Incorrect classification and fakes   All times are GMT - 5 Hours
Page 1 of 1
    

 
Jump to:  
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 vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


All pictures, text, design © Forum FMF 2006-2017


Powered by FMF