You will be forgiven for not having heard of, let alone given much thought to, a raw material called gallium. So, to explain: it’s a by-product of the bauxite-to-aluminium smelting process, it’s used in semiconductors and it is vital for the latest missile defence and radar technologies. Israel’s Iron Dome and the US Patriot Missile system rely on materials such as gallium to guard the skies against Iranian drones and Russian cruise missiles.