Brass than in brass produced by cementation. These may be "natural alloys" manufactured by smelting zinc rich copper ores in redox conditions. Many have similar tin contents to contemporary bronze artefacts and it is possible that some copper-zinc alloys were accidental and perhaps not even distinguished from copper. However the large number of copper-zinc alloys now known suggests that at least some were deliberately manufactured and many have zinc contents of more than 12% wt which would have resulted in a distinctive golden color. By the 8th–7th century BC Assyrian cuneiform tablets mention the exploitation of the "copper of the mountains"
Period 2 element alloys with aluminium, cadmium, copper and manganese are used to make high performance parts for aircraft, most notably the external tank of the Space Shuttle. Beryllium (Be) is the chemical element with atomic number 4, occurring in the form of Be. At standard temperature and pressure, beryllium is a strong, steel-grey, light-weight, brittle, bivalent alkali earth metal, with a density of 1.85 g·cm. It also has one of the highest melting points of all the light metals. Beryllium's most common isotope is Be, which contains 4 protons and 5 neutrons. It makes up almost 100% of all naturally occurring beryllium