Are there any stackers with the right equipment that offer a testing service in the Brisbane or Sunshine Coast area? I got a few items of gold and silver I’d like to know for sure if they’re real or fake!
Modern counterfeits get past XRF. The US anti counterfeit taskforce recommends PM tools that test conductivity. Of course that test only tests the intrinsic metal and doesn't mean your bar or coin wasn't made by Chinese pocketing the numismatic value e.g. gold half sovereigns and silver Morgans.
Conductivity can also be spoofed. You must do a cohort of tests starting with weight and dimensions. Can do specific gravity as well.
Surface conductivity/resistivity can be spoofed. I have not seen evidence measuring conductivity through the bar or coin can be spoofed. From what I have seen start with a ping test. Very hard to fake although requires experience. Next is a conductivity test. Two types of tests - surface and deeper. Next is a density(specific gravity) test. 2019 caveat - counterfeiters are certainly getting a handle on density. Next is Xray(XRF). Xray won't detect a well plated coin but will detect if metal proportions are just a little off e.g. British versus Arabian gold sovereign.
