Here's why:

* Properties of metals: Metals are generally shiny, malleable, ductile, good conductors of heat and electricity, and have a tendency to lose electrons in chemical reactions.

* Properties of niobium: Niobium exhibits all of these metallic properties. It's a silvery-gray, ductile metal with excellent conductivity.

While some elements can be tricky to classify, niobium clearly fits the definition of a metal.