Rwanda's National Bank commissioned this piece as part of a broader Olympic sports series timed to the Beijing Games. Niobium — a refractory metal more commonly found in steel alloys and superconductor research than in coinage — produces the distinctive colored surface without applied paint or plating; the hue develops through anodization, with voltage controlling the oxide layer thickness and therefore the final color.
Rwanda's National Bank commissioned this piece as part of a broader Olympic sports series timed to the Beijing Games. Niobium — a refractory metal more commonly found in steel alloys and superconductor research than in coinage — produces the distinctive colored surface without applied paint or plating; the hue develops through anodization, with voltage controlling the oxide layer thickness and therefore the final color.