Rhenium
A single crystal of rhenium made by the floating zone process (left), an ebeam remelted rhenium bar (center), as well as a 1 cm3 cube. Rhenium is a silvery-white, heavy transition metal that is one of the rarest elements in the Earth's crust. It was the last stable element to be discovered and is named after the river Rhine in Europe.Photo: Alchemist-hp