Pennyweight Act of 1878; only the Troy ounce and its decimal subdivisions remained official. The Troy ounce enjoys a specific legal exemption from metrication in the UK. The pennyweight is the common weight used in the valuation and measurement of precious metals. Jewellers use the pennyweight in calculating the amount and cost of precious metals used in fabricating or casting jewellery. Similarly, dentists and dental labs still use the pennyweight as the measure of precious metals in dental crowns and inlays. Pennyweight and grains are still used to weigh gooseberries in competitions in Cheshire, northwest UK. Over the Pennines in Yorkshire
Synthesis of precious metals However such high-energy neutrons can be produced only by particle accelerators.. In 1980, Glenn Seaborg transmuted several thousand atoms of bismuth into gold at the Lawrence Berkeley Laboratory. His experimental technique, using nuclear physics, was able to remove protons and neutrons from the bismuth atoms. Seaborg's technique was far too expensive to enable the routine manufacture of gold but his work is the closest yet to emulating the mythical Philosopher's Stone. Synthesis of precious metals The synthesis of precious metals involves the use of either nuclear reactors or particle accelerators to produce these elements. Ruthenium and rhodium are precious metals