Have you ever wondered why mercury’s chemical symbol on the periodic table is “Hg”? According to Live Science, the letters are derived from its Greek name, hydrargyrum. (Its modern name comes from the planet Mercury.)

The quicksilver element, which develops mainly in the form of cinnabar deposits, is the only metal on the periodic table that is liquid at room temperature. It has been used in thermometers, barometers, and light bulbs, but exposure can be extremely toxic to humans.