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
Nucleic acid test Nucleic acid test A nucleic acid test (NAT) or nucleic acid amplification test (NAAT) is a technique utilized to detect a particular nucleic acid, virus, or bacteria which acts as a pathogen in blood, tissue, urine, etc. The NAT system differs from other tests in that it detects genetic materials rather than antigens or antibodies. Detection of genetic materials allows an early diagnosis of a disease because the detection of antigens requires time for antigens to appear in the bloodstream. Since the amount of a certain genetic material is usually very small, NAT includes an amplification step of the genetic