insoluble black powder ?

[diverwild]

refining 18 K jewely polishing bags
Every time I precipitate gold out if AR using SMB، settle overnight، when I come to decant I see some kind powder go out with the solution as I decant، it is so light، with no weight at all، gold powder is at the bottom، it will not go with the flow، but this one is different، it has the color of gold، but it wont stay at the bottom when I decant !?.

 

[Refining Rick]

But it was dissolved in the A/R right? Was the A/R perfectly clear before adding SMB? Use a laser pointer to shine through the beaker to test.
But, it is not insoluble, as you said it dropped out after the SMB addition.
Secondly is it black or "gold colored"? I have dropped some dirty brown gold but have not had black gold powder (unless stannous testing counts).
Is it floating on top of the solution or swirling about in it? If it is on top, try and spritz with a spray bottle to knock it off the surface and let it settle again.
On a side note, I refined an old 10K cross pendent once that let copious amounts of untouched jet black powder in the beaker. Still not sure what it is. Very heavy and shiny black when washed and dried. My guess was ruthenium or antimony. Not sure how to check that one however.

 

[diverwild]

But it was dissolved in the A/R right? Was the A/R perfectly clear before adding SMB? Use a laser pointer to shine through the beaker to test.
But, it is not insoluble, as you said it dropped out after the SMB addition.
Secondly is it black or "gold colored"? I have dropped some dirty brown gold but have not had black gold powder (unless stannous testing counts).
Is it floating on top of the solution or swirling about in it? If it is on top, try and spritz with a spray bottle to knock it off the surface and let it settle again.
On a side note, I refined an old 10K cross pendent once that let copious amounts of untouched jet black powder in the beaker. Still not sure what it is. Very heavy and shiny black when washed and dried. My guess was ruthenium or antimony. Not sure how to check that one however.

solution is perfectly clean، it dropped after SMB، its not floating in the top، its settled with gold powder in the bottom، once I decant it floats leaving the heavy gold powder behind