January 24 Through February 4—TUCSON, ARIZONA: Annual show
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Thu Mar 28, 2024 3:48 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 6 posts ] 
Author Message
 Post subject: Preservation of amber
PostPosted: Sun Jan 27, 2013 5:39 pm 
Offline
New to the Forum or The Quiet Type

Joined: Fri Jan 18, 2013 8:52 pm
Posts: 4
Confession: There is too much I need to learn.
What is the best way to preserve amber? Mine is getting a cracked texture on the surface.
What is the best way to preserve opalized shells? These are not polished but in the original matrix and I do want to take care of them so that they will be intact when I give them to our local museum.
Do I need to monitor humidity? temperature?


Top
 Profile  
Reply with quote  
 Post subject: Re: Preservation of amber
PostPosted: Sun Feb 03, 2013 5:26 pm 
Offline
Gold Member

Joined: Sun Jun 28, 2009 9:56 am
Posts: 1284
First, avoid shocks and friction during transport/handling. In order to avoid accidents, better not manipulate specimens more than necessary.

Most minerals are best stored away from heat, frost, brutal temperature changes (be careful to lamps and radiators), humidity, and direct sunlight.

Also, acid-sensitive minerals should not be stored in furnitures made of highly acidic woods (that is to say woods which have a pH under 5).
Here's a link which features a table of woods pH (it's at the end of the document): http://www.npl.co.uk/upload/pdf/corrosi ... y_wood.pdf

Some sulfide minerals (especially some marcassite and pyrite) might occur in unstable form which slowly decompose releasing sulfuric acid, such unstable specimens should be stored separately from any acid-sensitive minerals (notably carbonates and stable sulfides)

Then, there are some specific mineral species that require special care:
-hygroscopic minerals that absorb humidity from the air
-water soluble minerals
-minerals that oxidize in the air oxygen or react to air humidity
-some hydrated minerals tend to loose their water
-some minerals tend to absorb greases when exposed to these
-light sensitive minerals
-dangerous minerals (toxic minerals, radioactive minerals, and fibrous asbestos minerals)


Here are three examples:
Some opals tend to loose their water: avoid heat and direct sunlight, best stored in a tightly closed vial filled with distilled water.
Fluorite hates brutal temperature changes which cause it to cleave (be careful to direct sunlight, lamps and radiators, avoid washing it with water, or at least make sure that the water is at ambient temperature), let's add that some fluorites tend to fade color under excessive lighting or in direct sunlight.
Some amber might darken by air oxidation, and this phenomenom seems to occur faster with exposure to light. You might store it in the dark inside an airtight zip bag to slow down the process.


Last edited by cascaillou on Mon Apr 22, 2013 6:55 pm, edited 3 times in total.

Top
 Profile  
Reply with quote  
 Post subject: Re: Preservation of amber
PostPosted: Sun Feb 03, 2013 7:58 pm 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21602
Location: San Francisco
I think many of the myths surrounding opal are just old wives tales.
If an opal has such a high water content, it will craze, loose its play of color or go milky if not kept in water, is not suitable for use in jewelry
There are many examples of Victorian jewels featuring pristine opals which have never been stored anywhere near water.


Top
 Profile  
Reply with quote  
 Post subject: Re: Preservation of amber
PostPosted: Fri Apr 19, 2013 3:37 pm 
Offline
New to the Forum or The Quiet Type

Joined: Fri Jan 18, 2013 8:52 pm
Posts: 4
Thank you all very, very much!!! I have at least started learning! I have already moved the pyrites specimens to a separate case. The large cubes of pyrite do not seem to be changing, but I moved the others. Would a good coat of water soluble acrylic help preserve the pyrite that is turning?
I tried to make an airtight case for a realgar crystal. Is it just oxygen that turns it to orange powder? It has not turned much in the 5 years that I have had it. It is on calcite. Any suggestions?


Top
 Profile  
Reply with quote  
 Post subject: Re: Preservation of amber
PostPosted: Mon Apr 22, 2013 6:47 pm 
Offline
Gold Member

Joined: Sun Jun 28, 2009 9:56 am
Posts: 1284
concerning the sulfides pyrite and marcassite, they are not a problem as long as they are stable. However, some specimens are unstable: those will have a strong iron/sulfur smell, and they will develop efflorescences at their surface. Only the specimens which are identified as unstable need to be stored apart from the rest of the collection.

Concerning realgar, it turns yellow and powdery with exposure to light, so it must be stored in the dark (so place it inside a drawer rather than inside the showcase).
Realgar is an arsenic mineral, it is not big deal as long as it is stable and clean, but if it turns powdery or if fine efflorescences appears on its surface, then the risk of accidental absorption will be increased. If so, it is recommended to wash hands after manipulating the sample (or maybe storing it inside a transparent plastic box might be more practical for handling).

here's a paper about realgar decomposition: http://www.minsocam.org/msa/collectors_ ... ealgar.htm


Top
 Profile  
Reply with quote  
 Post subject: Re: Preservation of amber
PostPosted: Sat Jun 08, 2013 3:47 pm 
Offline
New to the Forum or The Quiet Type

Joined: Fri Jan 18, 2013 8:52 pm
Posts: 4
The realgar is in a small glass cube with a walnut base and is held up by a brass stand. I will put on gloves, dust it off a little, and place the whole little case in the back of my cabinet with my other specimens. The tiny halogen lights only gets turned on about once every 3 weeks and not for very long. Halogen lights include from near ultraviolet to deep infrared wavelengths so I will check your reference and see if I need to cover the little case with a black cloth. It is not a large showstopper specimen.(It is about as big as my outstretched hand.) It is lovely, though and it always gets everyone's attention because most of them have heard of Arsenic used in its most sinister form :lol: .


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 10 guests


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