Acid test (gold) mark is tested by applying aqua fortis (nitric acid), which dissolves the mark of any item that is not gold. If the mark remains, it is tested by applying aqua regia (nitric acid and hydrochloric acid). If the mark is removed, then this test dissolves the gold, proving the item to be genuine gold. More accurate testing of the item for its fineness or purity can be done through the use of differing strengths of aqua regia and comparative testing of gold items of known fineness. The figurative meaning of the expression, where it is applied to tests of character,
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