How can l test gold dust? It’s from a stream in the San Bernardino Mountains from a large amount of black sands. It looks like gold in the pan but there’s a lot of pyrites also. It glitters in every ground sample, it’s everywhere. Acid tests don’t affect any of it. They have also separated out from black sands with a magnet. I want to determine if any part is gold.
I understand your problem. Oat gold is hard to differentiate from mica and pyrite because it is so small. However, under a very bright high-intensity light, it shows up as yellow and it glows. Pyrite is burnished and mica is usually shiny only on one side. If you flip it by blowing with a suction tweezer, it is dark. If you need more verification, I would go to a prospecting shop or possibly an assayer.
Updated on May 7, 2020
By John R Wilsdon