Description

As eye-catching, innovative and informative as its predecessors, Bionik, the exquisite purple 2012 addition to the 25 euro Silver Niobium series, pays fitting tribute to how evolution in the natural world acts as a prototype for technology.

Each year’s issue is composed of a disc of 7 grams of 998 pure niobium surrounded by a 9 grams of 900 fine silver outer ring. The brilliant colors of the disc are achieved by anodic oxidation—a precisely controlled electrochemical process that deposits a fine layer of oxidized niobium on the surface of the disc. The color is determined by the thickness of the layer. From 2003 through 2013, each year’s design was processed with a single color; beginning in 2014, the finely detailed images began to be two-toned, with selectively colored elements set off against a solid background of a complementary color.

Niobium was chosen for the core due to its workability as a coinage metal and its low reactivity (which prevents its corroding where it comes in contact with the silver ring). Niobium’s larger application is in the aerospace industry, making it a thematic fit with the series, whose designs have focused on achievements in science and engineering.

The coins are encapsulated, packed in a red case with a handsome grey slipcover, and comes with a certificate of authenticity.