In 2003, the Austrian Mint used the metal niobium in its commemorative coin. It was the first time niobium had been used in coinage. The coin is actually a bi-metallic coin with a silver ring and a centre made of niobium. It is the first Austrian coin coloured blue.
Niobium is a shiny white metal. However, with special treatment the surface of niobium can be made to change colour. In the case of the above-mentioned coin, the central niobium pill is blue.
Since then, 3 other such bi-metallic coins were made in Austria. The niobium part is green, purple and brown respectively.
obverse of 1st coin, blue
reverse of 1st coin, blue
obverse of 2nd coin, green
reverse of 2nd coin, green
obverse of 3rd coin, purple
reverse of 3rd coin, purple
obverse of 4th coin, brown
reverse of 4th coin, brown
# posted by Birdie @ 10:38 PM
