FMF - Friends of Minerals Forum, discussion and message board

[Matt_Zukowski]

The best packaging material for most specimens seems to be plastic of the sort in dry cleaner bags. Does anyone know how safe this plastic is for long term storage? Perhaps it degrades in a way that damages or leaves a residue on the specimen.

[Jesse Fisher]

To my experience, polyethylene plastic "dry-cleaner" bags are pretty stable. I have used them for at least 20 years to wrap and store minerals and have noticed no appreciable degradation of the plastic. I know some other types of plastics will degrade, such as polyurethane and polyvinylchloride (PVC). I believe there was a discussion of this topic on Mindat a number of months back, and a few folks with knowledge of polymer chemistry had comments on the subject of the stability of various plastics.

[Jim Prentiss]

Hello Everyone,

What about Saran Wrap in lieu of the dry cleaner bags? Are there any problems there?

Thanks,

Jim Prentiss

[GneissWare]

Because of the cling factor, it may be difficult to remove from fragile specimens

[lluis]

Good afternoon.

As always, answer is "it depends"
Formerly Saran wrap was a coplymer with vinylchloride.
Now is polyethylene.
Former with vinylchloride will release chlorhidric acid, and attack some minerals.
Later is pretty inocuous (although it will degrade, becoming fragile)

With best wishes

P.D: maybe biased answers, because I use Jousi boxes and now Mikon boxes :-)

[Les Presmyk]

Some years ago, there was quite a furor in the coin hobby/business (along with stamps and photographers storing 35mm slides) because it was discovered that the polyvinylchoride storage sleaves were degrading and leaving greenish slime on the collector coins and the same with color slides.

As like Jesse Fisher, I have had no problem with dry cleaner bag material for storing minerals.

[Screenname]

I keep all mine in a metal box, is that not Ok, they have been in there for years and still look as they did the day I put them in?

[Les Presmyk]

Metal is probably the best but probably heavier than other alternatives.

[Carles Millan]

Hi!

Since 1962 I've been keeping a lot of my specimens in small, colorless, not expanded polystyrene boxes and I can't notice any change yet. Near 50 years! They are species with all the usual chemical compositions, from native elements to silicates, including of course sulphides, fluorides, carbonates and so on.

Polystyrene is the transparent material used to manufacture CD/DVD cases and many ballpoint pens.

Polystyrene at Wikipedia:
https://en.wikipedia.org/wiki/Polystyrene
(link normalized by FMF)

[Jean Sendero]

Hi all,

what about specimens that contain marcasite? Often it seems that some specimens are composed by a mixture of marcasite and pyrite. These form acid and start to burn paper, cardborad, metal, etc.....What would be the best way to preserve them and avoid to see them turn into a pile of white powder?

A similar question is asked about native sulfur. The sulfur from San Felipe Baja California seems to be loosing it's crystal shape with time???
Thanks
Jean

[Ceri Roberts]

Hi there. new to all this. i can see there has been a long thread discussing storage but I wondered if any one could help me. I am thinking of storing each piece in a small cardboard box lined with cotton wool for protection. Can you see any problem with this? If you have used cardboard boxes like this any ideas where I can get them.

Cheers,

Ceri

[James Catmur]

Ceri

The problem with cotton wool is that you get fine hairs on the specimen that you then see wen you try to photograph it! I try to avoid the stuff and just use cardboard boxes

James

[David Von Bargen]

Yes, the cotton fibers can get on the specimens and if the matrix is a bit crumbly, the cotton can get pretty dingy looking. Mineral & Fossil Supply, Inc. in Denver has the cardboard boxes as well as the cardboard flats to put them in.

[GneissWare]

Lots of folks use sheet plastic (dry cleaners plastic bags) as wrapping material. It is inert, and protects the specimens. I store smaller specimens, wrapped in this plastic, in cotton-filled boxes. Larger specimens are put in shipping boxes, also wrapped in plastic.

On the issue of storing sulfides, one rule of thumb is that if it has a strong sulfur odor, you may want to get rid of it, as it will eventually decompose. Some people use desiccant packs, as moisture really exacerbates the decomposition problem, but this will likely only slow sown the inevitable demise of the specimen.

On a related theme, it is probably unwise to store sulfides and carbonates together in the same flat, particularly if the sulfide is emitting sulfur odor, because some H2SO4 will be forming in the closed box.

[Les Presmyk]

I also try to keep sulfides, especially marcasite, pyrrhotite and pyrite away from silver and copper specimens. Solid pyrite crystals are generally very stable but granualr pyrite matrix can be as reactive as marcasite or pyrrhotite.