31.1 (1 oz). BU – Brilliant Uncirculated. This amazing 1 Oz Silver coin is dedicated to some of the most famous world coins. This coin has a beautiful Black Ruthenium finishing with a Rainbow Finishing and comes in a case along with its Certificate of Authenticity. Strictly limited mintage to only 250 pieces worldwide. PLEASE NOTE : It is still possible to order this coin from the Mint. Waiting times average 4-5 weeks!