FMF - Friends of Minerals Forum, discussion and message board

[jtozier]

Hello all!

I am new hear and looking for some info specific to the type of crystals I will be working with.

Golden Calcite from Montana.

So far I have tried a vinegar bath and scrubbing with a brush. This left a sort of white haze. I also tried muriatic acid and this gave it a great golden smooth color but I am afraid it may make the crystals loose value if it is etching them?

So far I have heard to use.

Super Iron out
Citric Acid
Oxalic Acid

Which one? I am leaning towards trying citric acid next since it seems the least toxic. I watched a video on youtube of someone if Florida cleaning some calcite seashells with it and it appeared to work well.

I also have a question on repair. I was descending a very steep cliff section and slipped dropping a very large piece of calcite. Some pieces broke off and I was wondering if LocTite glass repair would be a good choice to reattach some of the crystals?

[kushmeja]

Have you tried using a high pressure spray water gun, like they use for screen printing and cleaning fabrics? You can buy one for like $50 online, and they're great. Based on your pics with the light scaling on some of the calcite, I'd say that the water gun would blast that right off. The only thing is that you would need to be careful not to have the pressure too high, or it would damage the crystals because calcite is fairly soft.

All of the chemical methods I'm aware of would run the risk of reacting with the surface of the calcite, causing it to etch or get a waxy/melted surface luster. Calcite is a base, so it will react with any acid, even fairly inert acids like vinegar or citric acid.

[jtozier]

The funny thing is I own a screen printing shop and yes I have used the spot gun. It really did not clean the minerals off the calcite.

[Bob Harman]

Welcome to this site! Rather nice specimen, but you must be careful cleaning all carbonates, and especially calcite!

Your discussion suggests you already may have over cleaned the example. Anyway, soak the specimen in soapy water for a day or two, then try a hi pressure cleaning gun with water. Start very gently and only in stout areas. Cleaning in areas of the crystals with incipient cleavages may be disastrous and the hi pressure might just completely cleave your calcite.
I would NOT use any (!) form of acid. I would NOT use iron out (no iron staining that I can see), or scrubbing with a stiff brush (as calcite is soft).

In my opinion, you probably have done all you can for that specimen so be content with it after the soapy water and hi pressure cleaning and a final rinse.

As to repair, it really is an individual specimen problem. If it is only one or two pieces that fit back together perfectly and make a great specimen, then you might try it, but on a mediocre specimen where the multiple pieces might not fit back together in a perfect manor, attempted repairs only magnifies the flaws. BOB

[jtozier]

Thanks, you know what my problem must have been not soaking prior to using the spot gun.

This one piece here is my favorite. However I feel like it is hardly held together. If you pick it up there is a little flex in the center by where the smaller crystals are. I was thinking of possibly ordering a tiny syringe to insert some glass loctite inside where the flex is happening.

This brings up another question, how do you all ship your crystals? I feel like the single pieces would be easy, buy anything that has multiple crystals seems like it would arrive broken.

[jtozier]

If a specimen has a haze to it, would it be ok to use a quick acid dip to remove that?

[Bob Harman]

If the calcite "haze" is a very thin crystal surface crust, I might try a 10-15 second swirl in vinegar. If the haze is within the crystal, no amount of anything will lessen or remove it.

CHRIS, I think you are trying to accomplish too much. On higher end examples, only an expert should try injecting hairline cracks or cleavages. In my opinion, not worth it on lesser examples. The repairs most likely will not look well, maybe making your specimen look worse.

As to shipping, most higher end examples are shipped insured and those with incipient cleavages are noted that shipping, even when very well packed, may arrive no longer intact. BOB

[jtozier]

Thanks, I appreciate all the help, this is a nice active forum you have here.

[Turbo]

0227 is a really nice piece. I would not alter that in any way, it would only decrease it's value. For many localities calcite does not have a lot of luster, and for some it is not expected to even for high end pieces. My Montana pieces have low luster, but at the same times it's the color and the chevrons that make the pieces unique.

As far as packing calcite, wrap generously in long lengths of clear plastic, but do not use cling wrap and do not wrap tightly. Then fit that into its own box with enough plastic around it that it can't shift around. Then that box can be in the larger shipping box suspended in packing peanuts.

[jtozier]

Thanks! 0229 is the other side of 0227, so it is nice all around and it sits very flat.

[Turbo]

[jtozier]

Just joined! The 110 Golden Calcite from the museum is awesome, I have seen one piece that large at my spot. I have no idea how anyone could manage getting that back to a vehicle without destroying it!

I have been finding ones that are buried in the dirt that will be perfectly smooth. Ones that are in open caverns that have etching from wind and sand and ones that are in enclosed pockets that may be clean or have mineral deposits on them. This area produces all different types in my opinion.

[roswellrockman]

In regard to repairs. You might try paleo- bond. It's supposed to be like a super superglue for fossils and minerals. I have not tried it yet but it has been highly recommended by several of my associates here in NM.

[Robert Seitz]

I've used Paleo bond to stabilize a few specimens with very friable limonite matrix. It appears to work, however, it changed the color of the matrix for a couple of specimens. I was warned to try on a small part of specimen before using so was aware with my pre-testing this would happen. I don't know what might happen with a calcite repair. Advise test before full use as always the case. Just like acid for that matter

[Philip Simmons]

As recommended by others, I wouldn't do any further chemical cleaning to the specimens. Iron Out will definitely etch the calcite, although not nearly as fast as HCl or even vinegar.