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Harry Lipke

Cleaning Quartz/gold

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One of my boys has a nice quartz/gold specimen that had a lot of rust in/on it.

I soaked it in Wink for a week, rinsed it off good, soaked it in baking soda for a couple of days.

Rinsed it off good. Was looking nice and white.(and gold...grin)

When it dried, it(the quartz) had a greenish yellow color to it... like something had oxidized on it.

I washed it off(as soon as the water hit it, the color disappeared) and let it dry again

Greenish yellow again.

So, I decided to boil it in water and see if that would do it.

When it dried, greenish yellow again.

 

What chemical action is going on?

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I think you misspelled the product.

Wink is an acrylic polymer.

 

Whink is a rust and stain remover.

Ingredients are:

Sodium bisulfate

Sodium hydrosulfite

Sodium chloride

Sodium Carbonate

Citric acid

Blue crystals

 

Source Whink MSDS

 

Added to water generates sulfur dioxide.

 

eric

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Yep, wrong spelling.

 

I thought active ingredient in Whink was hydrofluoric acid?  Which doesn't contain any of the chemicals you listed.

 

At least that is what I get from the Whink site?

 

Ok..  I think there two different Whinks.  The one you got the info on is a powder.  The one I used is a liquid.

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I stand corrected.

I gave the contents of the dry variety.

The liquid version has Hydroflouric acid as one component of the trade secret mixture.

 

As gold is an alloy, it is probable that the HF and other unknown chemicals are reacting with the alloy.

Looking in the CRC Handbook it reveals that silver reacts with HF and AgF is yellow, AgF2 is brown and Ag2F is yellow as well.

 

Mineral specimens are a hodge-podge of chemicals, so there could be other chemicals reacting as well.

And the other components of Whink are trade secrets. Who knows what is reacting with what?

 

Just a guess that the gold might have some copper in it reacting with something else in the Whink.

Copper and HF tends to be white and black compounds.

Iron could be involved and HF could turn it into iron flouride octahydrate which is green-black.

So the color might be a similar outcome as mixing a bunch of different color paints.

 

Keep in mind that HF is really bad for organics like the human body.

I always recommend reading the MSDS before using chemicals.

Having a CRC Handbook of Chemistry and Physics around is a good idea.

Used books are far cheaper than new and unless you are trying to be on the cutting edge of chemistry, older editions are just fine.

 

eric

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After a hour of boiling, the greenish tent is gone now.  Just a yellowish tint left.

 

That could be the silver fluoride?

 

Now I just need something to turn the silver fluoride clear :)

 

Thanks Eric

 

BTW, I am well aware of the dangers of hydrofluoric acid... BAD STUFF!!!

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No, using bottled spring water.

 

I read on a site for cleaning crystals that if you leave it in acid too long, it may turn yellow.  Said to soak in water for a week.

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