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Cleaning Pyrite

Posted by Andy K  
Andy K October 13, 2004 04:03PM
Hi everyone..

Just a quick question.

I have a large mass of Pyrite which is quite tarnished. How do I safely clean this to get it shining again (or is this impossible).

Please.. I'm not a chemist so all those nasty chemical solutions will be no good so does anyone know how to do this with general household stuff (but above all safely).


Andy K
Gunnar Färber October 14, 2004 08:06AM

put it in oxalic acid or in HCl both can help you.

Best Regards

alfredo October 14, 2004 05:40PM
Peruvians, probably the biggest exporters of pyrite to the USA and Europe, give most of their pyrite a bath in HCl before export. (I don't know the concentration they use or time taken.) You could try the acid sold everywhere for use in swimming pools - In the USA that is often a mixture of HCl and phosphoric acid.
Rob Woodside October 14, 2004 07:17PM
Sodium Dithionite will remove iron stains and is commercially available. When Bob Jackson hits a new pocket of Pyrite at Spruce, the pyrite is usually covered in limonite and he doesn't know until a dithionite or HCl bath whether the pyrite below is dull or lustrous. The lustre, if gone, cannot be restored and is the difference between the specimen being worth tens of dollars instead of hundreds.
Alan Plante October 15, 2004 05:21AM
Hi again, Andy

It would be helpful if you state where the specimen came from - and whether or not it is a matrix piece, the matrix important to the specimen. Knowing where the specimen came from, someone clicking in here might know exactly what you need to do for specimens from that locality.

Barring that, you might want to try some less aggressive cleaning agents first - like a scrub with a scouring powder that doesn't have anything harder than 5 on the Mohs Scale in it - then maybe some Super Iron Out if the scouring powder doesn't work.

With any mineral that is prone to rusting or tarnishing, a thorough drying is required immediately following cleaning - even if it is just setting the stuff out in the sun, or on a windowsill that is getting sun. So be sure to dry the pyrite after you get it cleaned.


sgibby October 15, 2004 02:50PM
Hi,do u know a chinese powder? U just sprinkle it on your pyrite and brush it. That's it. Cheap and easy way and not harmful your pyrite. We use this in Thailand.
Andy K November 09, 2004 04:46PM
Thanks everyone..

I actually got this from Lyme Regis in the UK (fell out of the cliff)

It's a bit massive but does contain some crystals..

Anyway.. more than enough idas..

Thanks again

Andy K
Franklin Roberts January 04, 2005 09:58PM
Watch out when soaking pyrite in acids, it'll give off hydrogen sulfide gas (rotten egg smell) which is highly poisonous. A bad side effect of H2S exposure is its tendency to desensitize the sense of smell so that its concentration seems to be decreasing when in fact it could be building up to toxic levels in the room. Play it safe and do this outdoors.

Franklin Roberts
Austin, Texas
Dave Baldwin January 18, 2005 01:02AM
I don't want to worry you Andy, but the pyrite from Lyme and surrounding areas is quite unstable and very prone to decomposition. It will start to develop efflorescence, may crack and fall apart. You can reduce the decompostion by placing it in an airtight container and/or avoid damp atmospheres.

Incidently, this decompostion of pyrite ultimately destroys many beautiful fossils from Lyme Regis and Charmouth.

Rock Currier January 19, 2005 09:27AM
Dear Andy,
If you pyrite is not already shiny, I know of no way you can make it shiny except by polishing it with standard lapidary procedures. I have had good luck with cleaning pyrite with the commonly available Lime Away cleaner. I believe it contains phosphoric acid to some extent. If your pyrites are in pretty good shape but a little old and not as shiny as you remember them to be, try this product. Be sure to soak them in clean water thoroughly after using the product to be sure it has been removed from all the cracks in the specimen. It also works on chalcopyrite if it is not too far gone.

Rock Currier
Patrick Slavenburg February 19, 2005 04:28PM

following up on this discussion: I bought a Bulgarian chalco with galena and sphalerite. The Chalco is a large separate crystal, covered with probably limonite (mostly). I cannot use an acid bath for fear of damaging the other crystals (which are physically separated from the chalco. Could I try cleaning the chalco with Sodium Dithionite or Lyme Away cleaner by just covering that particular chalco crystal, or does it need to lie in some bath for hours and hours ?

The Chalco crystal is quite big: 3-4 inches diameter, and it has a perfectly etched 2 inch galena attached to it, hence my eagerness to see if I can get lucky with a lustrous (or at least colorful) chalco. If you would have any other suggestions I'd be very much obliged !


Patrick Slavenburg
Rock Currier November 27, 2005 11:32PM
I know nothing about the Chinese powder you mention. Any information you could give me about it would be appreciated. It is difficult to understand what kind of powder or chemical that it might be that would quickly allow one to make pyrite shiny.
Keith Compton December 20, 2005 09:17AM
If the discloration is only due to a little oxidation then perhaps this may help.

Why not try cleaning it gently wth a toothbrush and toothpast (whitening type) and tepid water. Then lightly rinse and dry thoroughly - and I mean thoroughly.

I have found that it will work in most cases and I have yet to find a pyrite / chalcopyrite specimen damaged in this way.

As many of these whitening toothpastes are now made in China perhaps that is the white powder referred to.

The toothpaste has not worn away my teeth - so it shouldn't wear away your Pyrite!!
ben waitkus January 13, 2006 02:34AM
what elements (periodic table of the elements) do you use to make pyrite
David Von Bargen January 13, 2006 01:46PM
See the chemical formula here:
Al June 26, 2006 02:51AM
I have just tried the toothpaste method and it works well without any damage to the pyrite.
Paul Stahl September 21, 2006 12:36PM
Some safe substances I have been using to clean chalcopyrite of late are the commercially available extract of citrus peel general purpose cleaners available in all supermarkets. Soak the specimen for 3-7 days totally submerged in the liquid then scrub the specimen with a hard tootbrush before washing citrus extract off. After a good scrub rinse throughly in water and look at the shine on your specimen! Ive been using it for months with fantastic results. Even if you already have a high grade specimen you will notice a change.
Peter Haas September 26, 2006 08:52PM
A 50 g/l (i.e. 5% w/v) solution of citric acid does the same job in just a couple of minutes.
Gary Kutac October 01, 2006 04:34AM
I have several pyrite 'Floaters' and Spheres similar to the German ones on page 11 of the pyrite gallery. These were found in North East Texas (many of them 1 -2 inches in diameter). They have a rust on the surface of the crystals. Is this removeable? My young son just wants to smash them (they are beautiful on the inside).
Kyle Eastman October 01, 2006 05:24AM
There are certain chemolithotrophic(rock-eating) bacteria that decompose sulfides and are known to destroy the luster of pyrite and other minerals.
I would suggest sterilizing all pyrite specimens with ultraviolet light or some other method before storage or display to prevent damage! Interestingly, similar bactera have been shown to produce the CO2 that goes into the formation of copper carbonates--thus the banding in azurite and malachite represents season patterns of bacteria growth!
An interesting web site:
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