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
22 Mar-18:15:33 Re: franjungle collection (Firmo Espinar)
22 Mar-14:54:36 Re: collection of philippe durand (Philippe Durand)
22 Mar-13:41:20 Re: women's private collection sub-forum (Fiebre Verde)
22 Mar-13:27:25 Re: women's private collection sub-forum (Riccardo Modanesi)
22 Mar-13:23:29 Re: women's private collection sub-forum (Tobi)
22 Mar-13:16:51 Re: collection of philippe durand (Tobi)
22 Mar-13:00:48 Re: collection of philippe durand (Pierre Joubert)
22 Mar-12:44:16 Re: collection of philippe durand (Philippe Durand)
22 Mar-12:02:13 Re: women's private collection sub-forum (Vic Rzonca)
22 Mar-09:42:57 Re: women's private collection sub-forum (Tobi)
22 Mar-08:52:34 Re: women's private collection sub-forum (James Catmur)
22 Mar-08:22:59 Re: women's private collection sub-forum (Dontgogreen)
21 Mar-21:38:55 Re: stump the experts! what is it. (Matt_zukowski)
21 Mar-21:24:54 Re: stump the experts! what is it. (Catahoula)
21 Mar-21:23:43 Re: stump the experts! what is it. (Catahoula)
21 Mar-21:22:26 Re: common opal cluster (Catahoula)
21 Mar-21:19:19 Stump the experts! what is it. (Catahoula)
21 Mar-21:17:22 Re: common opal cluster (Peter Megaw)
21 Mar-21:08:38 Re: common opal cluster (Catahoula)
21 Mar-21:06:08 Re: common opal cluster (Catahoula)
21 Mar-20:57:04 Common opal cluster (Catahoula)
21 Mar-19:33:47 Re: women's private collection sub-forum (Joseph Doliveira)
21 Mar-18:46:27 Re: don lum collection (Don Lum)
21 Mar-18:42:09 Re: women's private collection sub-forum (J. G. Alcolea)
21 Mar-18:19:54 Re: women's private collection sub-forum (Alfredo)

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
52950


The time now is Mar 22, 2019 21:20

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
Iridiscent Goethite from Southern Spain
  
  Index -> The Ten Thousand Club
Like


View previous topic :: View next topic  
Author Message

Joan R.




Joined: 16 Mar 2007
Posts: 75
Location: Barcelona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 11, 2008 10:00    Post subject: Iridiscent Goethite from Southern Spain  

Last April 2007, a team of mineral collectors from Huelva extracted after a hard work excellent stalactitic-botrioidal goethites, in the Filón Sur Mine (closed from 2001), near Tharsis. They get out several specimens in a small cavity, that was only a 30 cm width in the goethite mass. Stalactitic goethite hungs inside.
Stalactites were embedded in a thick and fine orange mud that covered everything and everybody. They couldn’t see what they were extracting because mud not allowed to know if the stalactit was long or short, whole or broken... a good portion of luck played in this work. Some specimens, when washed, they showed intense iridiscence with colours like red, blue, green, mauve and gold. This locality hasn't produced significant samples in the last twenty years.



Stalactitic-botryoidal growth with intense, very bright, iridescence,
with metallic reflections of dominant colors between golden and blue.
Filón Sur Mine, Tharsis, Huelva Spain (05-10/2007)
Specimen size: 6.7 x 4.5 x 4 cm.

Old mining train in Tharsis (40’ film in Spanish - Video Google) :
https://video.google.es/videoplay?docid=-925978439510782157



Goethite Tharsis Huelva Outcrop.jpg
 Description:
Stalactites were embedded in a thick and fine orange mud that covered everything and everybody (...)
Photo: Fermín
 Viewed:  17012 Time(s)

Goethite Tharsis Huelva Outcrop.jpg



Goethite Tharsis Huelva NH60K8.jpg
 Description:
Stalactitic-botryoidal growth with intense, very bright, iridescent metallic reflections, whose colors vary between blue and red more pastel than is usual.
Filón Sur Mine, Tharsis, Huelva Spain. (05-10/2007)
Specimen size: 7.3 x 3.7 x 3.1 cm.
 Viewed:  17099 Time(s)

Goethite Tharsis Huelva NH60K8.jpg



Goethite Tharsis Huelva NA63K4.jpg
 Description:
Stalactitic-botryoidal growth with intense, very bright, iridescence that contrast with a later phase of smaller botryoidal growth, dust and of intense red color.
Filón Sur Mine, Tharsis, Huelva Spain (05-10/2007)
Specimen size: 7.2 x 3.3 x 3 cm.
 Viewed:  17078 Time(s)

Goethite Tharsis Huelva NA63K4.jpg



_________________
Joan Rosell
lengenbach(.)com
Grup Mineralògic Català
Back to top
Reply to topic Reply with quote
Like
   

alfredo
Site Admin



Joined: 30 Jan 2008
Posts: 724


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Feb 06, 2008 16:00    Post subject: Re: Iridiscent Goethite from Southern Spain  

Hello Joan! Thanks for posting these beautiful pictures. I've always had a fondness for iridescent iron oxides, even though I hardly ever find any as good as yours.

Question: Given the difficulties of studying thin surface films, has anyone actually studied the composition of the iridescent films on such stalactites? A lot of collectors call such films "lepidocrocite", without any evidence I'm aware of that that's what they really are. I have no hesitation calling these specimens "goethite", as Joan does, since that is the composition of the bulk of the stalactite. (The cream on top of a cake does not change the fact that most of it is still "cake".)

A similar question passes through my mind with regard to the iridescent films on some lavas - films that some "systematic" or "species" dealers are happy to sell as the mineral "siderazot" (iron nitride), even though evidence for the existence of that mineral seems to be as thin as the films it forms.

Anyone aware of modern studies on thin mineral films, please tell us.
Regards,
Alfredo
Back to top
Reply to topic Reply with quote
Like
   

Jordi Fabre
Overall coordinator of the Forum



Joined: 07 Aug 2006
Posts: 4256
Location: Barcelona


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Feb 06, 2008 16:32    Post subject: Re: Iridiscent Goethite from Southern Spain  

Alfredo,

Having the same doubt concerning the named "Lepidocrocite" I analyzed on the past this Goethites and them are pure Goethite, no traces of Lepidocrocite. I ignore if in some other place Lepidocrocite could appear with this appearance, but for sure, the Spanish ones are just Goethite

Jordi
Back to top
Reply to topic Reply with quote
Like
   
Display posts from previous:   
   Index -> The Ten Thousand Club   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 2006-2019


Powered by FMF