FMF - Friends of Minerals Forum, discussion and message board

[vic rzonca]

I bought this pale aquamarine on mica years ago at the East Coast Show, when the show was in the Springfield Civic Center. I have finally decided to try and clean it and realized it may not be as easy as a soak in Iron Out. Before I wreck it, does anyone have any advice on what not to do. I haven't tried to clean much mica and of course I'd like to make this piece look like a million bucks. Also, a guess on a more precise location, if possible, would help.

Thanks
Vic

[Michael Shaw]

Hi Vic,

Removing the iron stains from this one may be tough. I suspect much of the staining is within/between the muscovite plates. I haven't had any experience with muscovite and iron out.

As far a a locality guess, I would bet on Gilgit District, Gilgit-Baltistan, Pakistan. Probably not much more precise than the original location given when you acquired the piece.

Michael

[Jesse Fisher]

The specimen is almost certainly from the pegmatites around Nager, in the Hunza Valley, Northern Areas, Pakistan.

To clean the iron stain, I would start with Iron-Out. It may not do the complete job but certainly won't hurt it. Because the mica leaves will trap and hold any chemical solution, it will be important to give the specimen long and repeated soaks in clean water after any treatment. If a couple treatments with Iron-Out solution does not get all the stain, I would switch to a dilute solution of phosphoric acid (around 10%). You may need to leave the specimen in for a few weeks, but to my experience this will usually get any iron stain that has not been encapsulated by later mineral growth.

I would recommend against using either oxalic acid or HCL (muriatic acid). If the specimen is not absolutely free of either of these after treatment, they will bleed a bright yellow stain upon drying, which can be very difficult to subsequently remove.

[vic rzonca]

Maybe it is as simple as a soak in Iron Out, I didn't know what soaking might do to the mica. Thanks for the confidence to proceed, Jesse.

[GneissWare]

I've cleaned a number of rocks with mica. Sometimes the plates will start to separate, but it occurs slowly. I always check every hour or so at first, and every few hours thereafter. You can catch any problems that way, and remove the specimen from whatever chemistry you are using.

[Jesse Fisher]

muscovite is fairly resistant to most chemicals so I would not worry about iron out doing anything to it. It does not, however, stand up well to mechanical cleaning methods such as high pressure water gun or air abrasive.