The common test is to crush the rocks and pan the material to look for gold. This means you need to know the difference between mica, gold, and sulphides like pyrite when seen in the pan. From the HANDBOOK FOR GOLD PROSPECTORS IN WASHINGTON By WAYNE S. MOEN and MARSHALL T. HUNTTING 1975: "Many times the novice prospector is undecided whether the "yellow stuff" he is looking at is really gold or is something else. The yellow minerals that are most commonly mistaken for gold are pyrite,