2021 Opal Lunar Series - Year of the Ox 1oz Silver Proof Coin - Perth Mint. Sent with Australia Post Standard Small Box/Satchel. The item "2021 Opal Lunar Series Year of the Ox 1oz Silver Proof Coin Perth Mint" is in sale since Friday, March 5, 2021.This item is in the category "Coins\Coins\Australian\Decimal". The seller is "brucenmelb" and is located in North Melbourne, VIC. This item can be shipped worldwide.