Minerals containing aluminium are difﬁ cult to decompose so that aluminium can be extracted. This is because the metal has strongly electropositive ions and thus has a strong afﬁ nity for all of the non-metals with their electronegative ions. For this reason, samples of the metal were not produced until 1825 when the Danish scientist H. C. Oersted used metallic potassium to chemically reduce aluminium from one of its compounds. Consequently, in those days aluminium was very expensive and cost about £ 250/kg to produce, and was far more expensive than gold. It is reported that the more illustrious foreign visitors to the court of Napoleon III were privileged to use forks and spoons made from aluminium, whilst the French nobility had to be content with tableware in gold and silver. One still meets such cases of ‘ one-upmanship ’ even in the metallurgical world – quite recently I was told of a presentation beer tankard produced in the metal zirconium.