Barium Barium Barium is a chemical element with symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Its hydroxide, known in pre-modern times as baryta, does not occur as a mineral, but can be prepared by heating barium carbonate. The most common naturally occurring minerals of barium are barite (now called baryte) (barium sulfate, BaSO) and witherite (barium carbonate, BaCO), both insoluble in water. The name "barium" originates from the alchemical derivative
Sterling silver Netherlands, the Baltic, Germany, and even deeper regions of central Europe." The sterling alloy originated in continental Europe and was being used for commerce as early as the 12th century in the area that is now northern Germany. In England the composition of sterling silver was subject to official assay at some date before 1158, during the reign of Henry II, but its purity was probably regulated from centuries earlier, in Saxon times. A piece of sterling silver dating from Henry II's reign was used as a standard in the Trial of the Pyx until it was deposited at the