Why does this article begin talking about Uranium and lead and then immediately non sequitur into tungsten? There must be something I'm missing?
Uranium and tungsten are the 2 metals which have about the same density as gold, so they can be used to fake gold. The only alternative would be to use alloys of rhenium, osmium, iridium or platinum (or also neptunium, but that is too expensive and too radioactive), but that would be pointless because such alloys would be too expensive.
Nevertheless, when I have read the paragraph for the first time, I have not spotted the error, because it is also true that tungsten is weakly radioactive.
The majority of the chemical elements heavier than the rare-earth elements, with a few exceptions (lead, gold, mercury and iridium) are weakly radioactive, but their radioactivity is several orders of magnitude lower than that of thorium and uranium.
http://news.chinatungsten.com/en/tungsten-dart-news/46-tungs...