Metallurgist Grigory Raykhtsaum shows Smithsonian three different ways to test if something is solid gold: a color test, a thermal conductivity test, and a particle test. It’s all computerized now so all he has to do is scan the object to get a read on the color, zap it with an electrical current to measure the conductivity, and scrape a bit off to have it analyzed in a powerful microscope.
source: gizmodo.com by Casey Chan
The Fat Cat Collective 