Goldsmith
Compared to other metals, gold is malleable, ductile, rare, and it is the only solid metallic element with a yellow color. It may easily be melted, fused, and cast without the problems of oxides and gas that are problematic with other metals such as bronzes, for example. It is fairly easy to "pressure weld", wherein similarly to clay two small pieces may be pounded together to make one larger piece. Gold is classified as a noble metal—because it does not react with most elements. It usually is found in its native form, lasting indefinitely without oxidization and tarnishing.
Alkali metal
Lithium, the lightest of the alkali metals, is the only alkali metal which reacts with nitrogen at standard conditions, and its nitride is the only stable alkali metal nitride. Nitrogen is an unreactive gas because breaking the strong triple bond in the dinitrogen molecule (N) requires a lot of energy. The formation of an alkali metal nitride would consume the ionisation energy of the alkali metal (forming M ions), the energy required to break the triple bond in N and the formation of N ions, and all the energy released from the formation of an alkali metal nitride is from the lattice energy of the alkali metal nitride. The lattice energy is maximised with small, highly charged ions; the alkali metals do not form highly charged ions, only forming ions with a charge of +1, so only lithium, the smallest alkali metal, can release enough lattice energy to make the reaction with nitrogen exothermic, forming lithium nitride. The reactions of the other alkali metals with nitrogen would not release enough lattice energy and would thus be endothermic, so they do not form nitrides at standard conditions. Sodium nitride (NaN) and potassium nitride (KN), while existing, are extremely unstable, being prone to decomposing back into their constituent elements, and cannot be produced by reacting the elements with each other at standard conditions. Steric hindrance forbids the existence of rubidium or caesium nitride. However, sodium and potassium form colourless azide salts involving the linear anion; due to the large size of the alkali metal cations, they are thermally stable enough to be able to melt before decomposing.