Apothecaries' system between actual and nominal weight. In the 19th century, most European countries or cities still had at least a "commercial" or "civil" system (such as the English avoirdupois system) for general trading, and a second system (such as the troy system) for precious metals such as gold and silver. The system for precious metals was usually divided in a different way from the commercial system, often using special units such as the carat. More significantly, it was often based on different weight standards. The apothecaries' system often used the same ounces as the precious metals system, although even then the
Synthesis of precious metals normal to allow used nuclear fuel to stand for about five years before reprocessing, much of this activity will decay away leaving 4.7 MBq of Rh and 5.0 MBq of Rh. If the rhodium metal was then left for 20 years after fission, the 13.3 grams of rhodium metal would contain 1.3 kBq of Rh and 500 kBq of Rh. Rhodium has the highest price of these precious metals ($25,000/kg in 2015), but the cost of the separation of the rhodium from the other metals needs to be considered. Palladium is also produced by nuclear fission in small percentages, amounting