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 2 Metal Gear Acid 2 , stylized as METAL GEAR AC!D², is a turn-based collectible card stealth game developed by Kojima Productions and published by Konami for the PlayStation Portable in 2005. A Java ME version for mobile phones was released by Glu Mobile in titled "Metal Gear Acid 2 Mobile". "Acid 2" is the sequel to the original "Metal Gear Acid", with the story set sometime after the events of the previous game. Like its predecessor, it follows an alternate continuity separate from the mainline "Metal Gear" series. The game uses a completely new cel-shaded graphic engine, replacing the darker