What is the value of a serving spoon made by Roneusil in Germany?

Answer 1

Single spoon probably somewhere between 10 - 20 US dollars on European market, I can't tell about US. Just to make things more clear: Roneusil is not the brand of the company that produced the spoon but it's sort of registrated trademark of the material that spoon is made of. Originally it had been used by Rochling factory as a shortcut of "Rochling Neusilber", where "neusilber" means literally "new silver", an alloy which looks very much like silver but contains none of it, today such alloy is generally called alpacca (see Wikipedia for more info). As the trademark laws were not so sophisticated that days, this "trademark" describing material can be found on products from different German manufacturers from that period (roughly estimated, from 1910).