Amalgam (chemistry) gold") would not be extractable from ore using hydro-mechanical methods. Large amounts of mercury were used in "placer mining", where deposits composed largely of decomposed granite slurry were separated in long runs of "riffle boxes", with mercury dumped in at the head of the run. The amalgam formed is a heavy solid mass of dull gray color. (The use of mercury in 19th century placer mining in California, now prohibited, has caused extensive pollution problems in riverine and estuarine environments, ongoing to this day.) Sometimes substantial slugs of amalgam are found in downstream river and creek bottoms by amateur wet-suited
UCPH Department of Chemistry moved several times, usually to better surroundings. In 1962, Universitetets Kemiske Laboratorium moved to its present location in the H.C. Ørsted Institute (HCØ), named after Hans Christian Ørsted who discovered electromagnetism in 1820. It is less well known that H.C. Ørsted was also an able chemist, and that he was in fact the first person to isolate the element aluminium. UCPH Department of Chemistry The Department of Chemistry () is a department under the Faculty of Science, University of Copenhagen. It is the largest basic research institute in chemistry in Denmark, and is responsible for the teaching of chemistry at