With gold and silver there is absolutely nothing stopping you from testing it, you could even take it to a local assay office, or if you're paranoid like I am, do it yourself using nitric acid, copper and water, I think that mixture only works for silver though and you need to make sure you wear a mask of some kind so you don't breath in any fumes from the nitric acid.
That is awesome, thank you for sharing your method. I really do wonder how much gold / silver has been falsely sold to people.
Plenty of ways to test gold and silver so the metal itself is really transparent ( not literally of course ) it's just organisations like the central banks that aren't.
+1