Black stained gold

[medic7a]

Can anyone ID the black stains on the gold?



I sure would appreciate it. My guess is its mercury, but I have been known to be wrong from time to time.

 

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[mtau]

It could be coated with manganese as:

 

[bug]

manganese and iron oxides no doubt. Its common in some of the ancient dead rivers like up in Iowa Hill and old river deposits where the minerals leached down.

 

[GrizzlyGremlin]

I agree probably manganese. Awsome looking gold though!!! I would save it as is. Maybe test it. Gold in natural rare form can fetch much more than spot price. Plus a vial of black flakes is a great beer conversation piece!

 

[Hoser John]

Just dip'm in laundry bleach-sodium hypochlorite- and that'll clean'm up. Nitric/hydrochloric also but more caution needed. John

 

[Gravelwasher]

I get some black stained au around the Placerville area too. You really have to keep an eye out for it and be in descent lighting or you will miss the darkest pcs. Gold with mercury will be silver in color. Good luck

 

[medic7a]

Thanks for the help guys

 

[Goldwasher]

I get some black stained au around the Placerville area too. You really have to keep an eye out for it and be in descent lighting or you will miss the darkest pcs. Gold with mercury will be silver in color. Good luck

took the words right out of my fingertips..

 

[medic7a]

I did almost miss them. I had dug it out of a thin rusty hardpack on top of some bed rock and ran the cons through a cal bucket sluice and thought it was just chunks of magnetite at first.

 

[Fullpan]

I found the same thing only one time (about the same amount as in your pic) on SF Yuba. Finally rubbed the pieces hard on my steel pan and saw the gold.
Should have kept them, as is, - pretty unique conversation piece as Grizzly says. Question "hey, whatcha got there?" Answer
"Black gold" - sounds cool.

 

[medic7a]

I cleaned a few of the pieces with bleach just for the heck of it. About half of them were covered in mercury under the manganese. But the bleach worked great. Learn something new everyday.

 

[Hoser John]

Upriver from Purdone crossing,Ruck a Chucky Rapids,Deadwood creek creek as seen many places. When ya see a panning cleanup pile always check it in these areas as most folks don't want that ugly black stuff but I sure do!!John