Drops of mercury. Droplets of mercury of various sizes on a black surface. Mercury is used in electrical apparatus, catalysis, poisons and dental amalgams. Mercury, or quicksilver, is a dense, silvery metal which is liquid at room temperature. It freezes at -38.9 degrees Celsius. The metal has a surface tension which is so high as to make the smaller droplets form almost perfect spheres. Mercury is obtained commercially from the mineral cinnabar (mercury sulphide). Mercury, along with most of its compounds, is highly toxic to humans. Mercury is a transition metal belonging to the zinc group of the periodic table and has the chemical symbol Hg.