The nickname for the element mercury is "quicksilver." Mercury's atomic symbol, Hg, is derived from the Greek word "hydrargyrum," which means "liquid silver." It is the only metal that is a liquid at room temperature.
Mercury has been known since antiquity, when alchemists tried to turn the metal into gold and silver. It is rarely found in pure form in nature; rather, it's mostly obtained from cinnabar (HgS.) Mercury is toxic to humans. It can enter the body through digestion, inhalation or through the skin. Symptoms of mercury poisoning include nausea, headaches, tremors and ulcerations. If enough mercury is accumulated in the body, it can eventually cause death.