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


Spanish message board






Newest topics and users posts
18 Mar-08:12:52 Green seam. Looks like it in a state of decay. (Ning)
18 Mar-06:47:13 Mineralogy & museums 10 - cardiff - 12th-13th august 2024 (Roy Starkey)
18 Mar-02:50:32 Re: collection from dany mabillard (Dany Mabillard)
17 Mar-01:57:58 Re: collection of volkmar stingl (Volkmar Stingl)
15 Mar-14:27:47 Re: collection of philippe durand (Philippe Durand)
15 Mar-13:49:04 Re: collection of firmo espinar (Firmo Espinar)
15 Mar-09:18:42 Re: collection of michael shaw (Michael Shaw)
15 Mar-03:45:43 The mizunaka collection - rhodochrosite (Am Mizunaka)
14 Mar-21:29:31 Re: monthly mineral chronicles, mineral guides and more... (Crocoite)
14 Mar-14:47:27 Re: collection of philippe durand (Jordi Fabre)
14 Mar-13:56:01 Re: collection of philippe durand (Philippe Durand)
14 Mar-11:24:43 Re: collection of philippe durand (Jordi Fabre)
14 Mar-08:55:22 Re: collection of michael shaw (Michael Shaw)
14 Mar-08:44:47 Re: the mim museum in beirut, lebanon (Mim Museum)
14 Mar-07:24:12 Re: collection of volkmar stingl (Volkmar Stingl)
14 Mar-02:30:15 The mizunaka collection - quartz (Am Mizunaka)
14 Mar-02:20:37 Re: collection of volkmar stingl (Tobi)
13 Mar-23:40:08 Re: collection of volkmar stingl (Volkmar Stingl)
13 Mar-14:22:58 Re: don lum collection (Don Lum)
13 Mar-14:02:43 Re: collection of philippe durand (Philippe Durand)
13 Mar-00:57:48 The mizunaka collection - quartz (Am Mizunaka)
12 Mar-07:36:06 Re: can you recommend a lab to analyse specimens (Luiz Oliveira)
11 Mar-16:19:18 Re: collection of philippe durand (Riccardo Modanesi)
11 Mar-15:18:26 Re: collection of philippe durand (Philippe Durand)
11 Mar-15:13:07 Re: collection of philippe durand (Philippe Durand)

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
111630


The time now is Mar 19, 2024 02:15

Search for a textSearch for a text   

A general guide for using the Forum with some rules and tips
The information provided within this Forum about localities is only given to allow reference to them. Any visit to any of the localities requires you to obtain full permission and relevant information prior to your visit. FMF is strictly against any illicit activities related to collecting minerals.
Cleaning Cookeite over pink Tourmaline
  
  Index -> Off-Topic and Introductions
Like
12


View previous topic :: View next topic  
Author Message

Ning




Joined: 11 Jan 2023
Posts: 19

View user's profile

Send private message

PostPosted: Jan 13, 2023 21:41    Post subject: Cleaning Cookeite over pink Tourmaline  

I thought I was really clever picking up this specimen for cheap in a Bangkok mineral shop. I thought it was calcite covering a ton of gemmy pink tourmaline terminated points. Put it in a vinegar bath and nothing happened. Not calcite then...

After a bit of investigation I think It may be Cookeite. I've had a few Acids recommended to me such as Hydrofluoric and Trifluoroacetic. But these look terrifying and not for a novice such as me, so that's a hard No. My only other option seems to be a light touch with a Dremel. Also slightly terrifying but I do have a steady hand.

Can anyone think of anything else?



IMG_0543.JPG
 Mineral: Tourmaline, Cookeite, Feldspar
 Dimensions: 25x10x15 cm
 Description:
 Viewed:  5184 Time(s)

IMG_0543.JPG


Back to top
Reply to topic Reply with quote
Like
   

Jesse Fisher




Joined: 18 Mar 2009
Posts: 628
Location: San Francisco


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 13, 2023 22:33    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

Unfortunately, cookeite is essentially a micro muscovite, and muscovite is largely impervious to most chemical treatments, even HF. The only way I have ever found to remove the stuff is by repeated soaking in hot water (which sometimes expands the mica) followed by a glass bead air abrasive. It's a slow process!
Back to top
Reply to topic Reply with quote
Like
2
   

Joseph DOliveira




Joined: 29 Jan 2012
Posts: 294
Location: Hanmer, Ontario


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 13, 2023 23:25    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

I agree, glass bead blasting may do the trick,
as the glass beads should not damage the tourmaline.

Jesse Fisher wrote:
Unfortunately, cookeite is essentially a micro muscovite, and muscovite is largely impervious to most chemical treatments, even HF. The only way I have ever found to remove the stuff is by repeated soaking in hot water (which sometimes expands the mica) followed by a glass bead air abrasive. It's a slow process!

_________________
Joseph D'Oliveira
Hanmer, Ontario
Canada
Back to top
Reply to topic Reply with quote
Like
   

alfredo
Site Admin



Joined: 30 Jan 2008
Posts: 977


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 14, 2023 00:18    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

Cookeite is a member of the chlorite group, not a mica. I've dissolved other chlorites (clinochlore-chamosite) in hot sulphuric acid, but whether that would also work on cookeite, I'm not sure.
Back to top
Reply to topic Reply with quote
Like
   

Jesse Fisher




Joined: 18 Mar 2009
Posts: 628
Location: San Francisco


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 14, 2023 01:04    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

I am not sure that I would recommend using hot sulfuric acid any more than HF to anyone who does not have access to a "professional" grade laboratory setup and training in proper lab safety technique.
.
Back to top
Reply to topic Reply with quote
Like
1
   

Ning




Joined: 11 Jan 2023
Posts: 19

View user's profile

Send private message

PostPosted: Jan 14, 2023 13:04    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

Thanks for the responses!

I live on a tiny island in Thailand, so I don’t have access to a glass ball blaster unfortunately. Though I do know a few chemists and biochemists on the island. Perhaps they could hold my hand of I go down the acids route. For now, I think my safest bet is to experiment at the edges with a Dremel with a flex arm and some small diamond burs.

I bought this as a fun project and I quite like the mystery of the rock if upon Dremel failure if I leave it mostly untouched.
Back to top
Reply to topic Reply with quote
Like
   

Paul Bordovsky




Joined: 07 Nov 2008
Posts: 46


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 15, 2023 10:58    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

The cookeite can be removed in some cases, by mostly mechanical means, but very carefully. This Kashmiri tourmaline was encrusted completely on the back side, and substantially on the display side. Leonard Himes prepared this for me using a high pressure water gun in conjunction with some other process. I don't think he used any dangerous or harsh chemicals. I think he did a very nice, skillful preparation. You might try contacting him and inquire about his services.


Bordovsky before 1.jpg
 Mineral: Tourmaline
 Description:
Kashmir
11.5 cm
 Viewed:  4900 Time(s)

Bordovsky before 1.jpg



Bordovsky before 2.jpg
 Mineral: Tourmaline
 Description:
Kashmir
11.5 cm
 Viewed:  4905 Time(s)

Bordovsky before 2.jpg



kashmiri tourmaline.jpg
 Mineral: Tourmaline
 Description:
Kashmir
11.5 cm
 Viewed:  4964 Time(s)

kashmiri tourmaline.jpg


Back to top
Reply to topic Reply with quote
Like
4
   

alfredo
Site Admin



Joined: 30 Jan 2008
Posts: 977


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 15, 2023 12:47    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

Get it professionally analysed and make sure it really is cookeite, and not the closely related species borocookeite! When the pink tourmalines from Malkhan in Siberia started coming out, dealers quickly cleaned off the ugly white coatings on the tourmaline, which later turned out to be the new mineral species borocookeite, and every rare species collector in the world wanted a piece. But unfortunately they had almost all already been cleaned and the borocookeite thrown away. In North America only Excalibur Minerals in New York had saved some of that ugly crust from there, so they had a monopoly on sales of the new species. ;))
Back to top
Reply to topic Reply with quote
Like
1
   

Ning




Joined: 11 Jan 2023
Posts: 19

View user's profile

Send private message

PostPosted: Jan 16, 2023 22:20    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

Thanks for the replies, that specimen is gorgeous! I’ve not seen a color combination like that before. Really striking!

Professional appraisal/cleaning Isn’t something I’d considered. I had a nice chat with the owners of a mineral lab in Singapore a while ago. I could ask them if they think it’s worth cleaning.
Back to top
Reply to topic Reply with quote
Like
2
   

Tobi
Site Admin



Joined: 07 Apr 2009
Posts: 4087
Location: Germany


Access to the FMF Gallery title=

View user's profile

Send private message

PostPosted: Jan 17, 2023 03:03    Post subject: Re: Cleaning Cookeite over pink Tourmaline  

I understand Alfredo's worries concerning the destruction of a new mineral species. But if that crust is not something new or rare, a professional procedure of removing it might reveal a really beautiful piece of tourmaline. The photos Paul posted above are a great sample that demonstrates how an encrusted chunk of rock becomes a top piece of a precious and very beautiful mineral!
Back to top
Reply to topic Reply with quote
Like
2
   
Display posts from previous:   
   Index -> Off-Topic and Introductions   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 2006-2024


Powered by FMF