Approximately 50 gram sample first leached in straight HCL, to the best of my knowledge palladium is the only sister that will give herself up to this single acid.
Gold and silver will not going to HCL as a single acid.
After filtering, added a small piece of copper to the leach, nice black precipitate, now I'm aware of the palladium.
The solids from the filter have gone into aqua regia, the leach is quite orange in color, OK I have platinum.
Now I've added sulfamic acid to kill the nitric acid, now waiting for everything to cool before filtering. Once I have a clean liquor I'll add a couple of crystals o ferrous sulphate/
If the ferrous sulphate shows me gold is present, then I'll keep adding more until there's no more precipitate coming down.
These tests are to tell me which elements are present.
Top two images copper precipitating palladium, bottom image filter solids now in AR, if you upsize the image you might actually see the gold.
Only not gold your expecting to see, but it's there.