# Nitric turns purple



## Harvester3 (Jan 24, 2009)

Greetings,
I have 3 small buttons of gold (and copper and other apparently) which I put in a nitric bath to try to clean up. 
What is it that turns the nitric purple? 
Also, the white fines hanging out on bottom of the container; silver?
much thanks


----------



## Noxx (Jan 24, 2009)

Colloidal gold is purple... I'm not sure about the nitric...


----------



## Harvester3 (Jan 24, 2009)

So, if colloidal gold, nitric a bit strong? I did have it on a coffee warmer...
Thanks so much


----------



## Noxx (Jan 24, 2009)

No nitric acid alone won't dissolve gold.

Can you provide a picture ?


----------



## Harvester3 (Jan 24, 2009)

Here's a couple. It's purpler than the photo indicates. I'm not much of a photographer. 
Thanks again


----------



## butcher (Jan 24, 2009)

is this nitric homade? maybe chloride contaminated?


----------



## goldsilverpro (Jan 24, 2009)

Purple colloidal gold is produced when dissolving bars in nitric acid that contain small amounts of gold and large amounts of silver, copper, or other base metals. It's a particle size thing. I don't know where the milkiness comes from. It looks like metastannic acid produced from dissolving tin in nitric.


----------



## Harvester3 (Jan 24, 2009)

The nitric is home made. Hasn't acted like the last batch tho.
The largest chunk has a lot of copper and silver in it, so that makes sense. The two smaller pieces are 80% Au. I shouldn't have bathed them together.
Maybe my nitrate was funky when I made the nitric?


----------



## Platdigger (Jan 24, 2009)

Your homemade nitric could have chlorides and therefore disolved a bit of gold.
Randy


----------



## lazersteve (Jan 25, 2009)

The color looks very similar to silver chloride that has been exposed to sunlight.

A very similar color is obtained when silver chloride is dissolved in ammonium hydroxide.

Did you use tap water when making your nitric acid?


Steve


----------



## Harvester3 (Jan 25, 2009)

I used water from the same container (distilled) as the batch previous, however the two batches seem to react differently. Somethings wrong somewhere with my nitric huh?


----------



## butcher (Jan 25, 2009)

after gold removed maybe take small sample try adding salt to this and see if silver precipitates ( After your gold removed), then maybe mix with Hcl evaporate treat as aqua regia, if as chloride unable to filter tin possible, lead and silver should ppt as dilute chlorides this may give you clues as to what you have ?


----------

