Period 6 element also dissolves in alkaline solutions of cyanide, which have been used in mining. Gold dissolves in mercury, forming amalgam alloys. Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to confirm the presence of gold in items, giving rise to the term "the acid test." Gold has been a valuable and highly sought-after precious metal for coinage, jewelry, and other arts since long before the beginning of recorded history. Gold standards have been a common basis for monetary policies throughout human history, later being supplanted by fiat currency starting in
Metal Gear Acid Metal Gear Acid , stylized as METAL GEAR AC!D, is a turn-based collectible card tactical RPG video game developed by Konami Computer Entertainment Japan for the PSP handheld game console. The game was first unveiled at E3 in May 2004, and was released in Japan on December 16, 2004, in North America on March 22, 2005, and in Europe on September 1, 2005. It was the first game in the "Metal Gear" series for the PSP. A Java ME version for mobile phones was released by Glu Mobile in titled "Metal Gear Acid Mobile". "Acid" focuses on turn-based tactics, using