Fake gold bars are usually made of gold-plated tungsten because the density of tungsten, which is 19.25 times that of water, is very similar to gold’s density of 19.30. This makes tungsten the most suitable metal to create counterfeit gold bars whose dimensions and weight are very close to gold.
ECM testing machines have been very effective testing tools in detecting such tungsten bars because tungsten has a much lower conductivity compared to gold (18.52 vs 44.7 MS/m). Thus, as ECM testing machines have become more mainstream, it became easy to detect gold-plated tungsten bars.
With the prevalence of ECM testing machines, counterfeiters are now optimizing fake gold bars to fool testers. These bars were made of about 90% copper which has a theoretical conductivity of 59.1 MS/m which is one of the few metals that has a higher conductivity than gold. By carefully mixing copper with other lower conductivity metals and impurities, it is easy to reproduce gold’s theoretical conductivity of around 44.7 and pass the ECM test.
Phi Beta Iota: We have been following fake gold every since Tim Geithner was reported to have sold watered down gold bars out of Federal Reserve New York. We note with concern that gold-backed certificates exceed actual gold by 600 to 1. And now we note with concern that fake gold is passing all the tests. Buyer beware.