monovalent gold

[hodhod1403]

Nothing here looks like Gold.
If there is any Precious Metals in there you can put in a piece of Copper and they will cement out.
Just make sure it is acidic

I put a copper foil in the acid solution that contains gold(|) . After 24 hours, the solution turned black and the copper is dissolving and black particles have settled under it. Question? Why do you think the solution turned black and how long does it take to dilute it?

 

[Yggdrasil]

I put a copper foil in the acid solution that contains gold(|) . After 24 hours, the solution turned black and the copper is dissolving and black particles have settled under it. Question? Why do you think the solution turned black and how long does it take to dilute it?

I can't say why the solution turned black.
But the black particles may or may not be Gold.
Have you had a proper stannous test yet?

 

[4metals]

As @tmj883 pointed out there are deposits of Carlin type gold in Iran and you can find an excellent description HERE. There are some interesting and concerning points in the article, first and foremost the gold is contained in arsenic rich pyrite. In case the OP was not aware arsenic when put into acids, (hydrochloric, nitric, and sulfuric) produces a TOXIC arsine gas.

For your own safety stop putting these samples into acid!

Second the article mentions this type of deposit typically runs 0.20 to 0.25 ounces of gold per ton. At these concentrations you are looking to detect by crude analytics, gold in the range of 3.5 milligrams per pound of sample. Not likely to succeed.

So while it is likely true, the geology of the region we ASSUME the OP is in may contain gold in quantities that, as Deano said, are difficult to recover. Recovering gold from these deposits will require a lot of financial investment from larger corporations experienced working these type deposits.

More important @hodhod1403 consider the consequences of putting arsenic in acid!