Differentiating Argentium from Traditional Sterling

Hi, as I was working today, I needed to figure out which alloy a
piece of metal was. I realized that we have yet another method for
differentiating between Argentium Sterling and traditional sterling:
sand, scrape, tripoli, or otherwise abrade the surface to make sure
there is not a fine silver surface coating. Torch heat the metal,
being sure to take the flame off the metal occasionally, to let
oxygen at it. If the metal is regular sterling, it will turn black,
and stay black. If the metal is Argentium Sterling, it may go black,
but if you keep heating it, it will turn white again. This may sound
crazy. Heck, it seemed crazy to me the first time I noticed this
phenomenon! It is true, though. As you keep heating, the germanium
and germanium oxide do their thing, and the metal turns white.

Cynthia Eid