Finishing touches make all the difference
The Perth Mint applies different finishes to precious metal coins . A ‘ finish ’ is a surface treatment that enhances the appearance of the coin ’ s design .
Techniques that achieve the desired effect require expert skills and specialist equipment . Here is our quick guide to various finishes that appear regularly on our numismatic releases .
In precious metals minting , we go to great lengths to define and enhance designs with different finishes as a measure of the coin ’ s superior quality and desirability .
PROOF
A coin with a proof finish is the Rolls Royce of minting . This type of coin is generally recognised by its delicately frosted ( matt ) raised design elements , which are thrown into prominence by a shiny , mirror-like table .
Production of proof quality coins is an involved process requiring specially prepared blanks that are buffed to a highlypolished state . Manufacture of proof dies is extremely intricate .
A die is a hardened metal stamp featuring a reversed impression of the coin design . In creating a proof die , the impression is covered with transparent tape . Using a surgical knife , the tape covering what will be the raised design elements is gradually removed with a steady , skilled hand . The exposed design is then sandblasted to create a frosted effect that will be replicated during the coin strike .
The remainder of the tape is removed and the table area of the die is polished with ‘ lapping ’ sticks and diamond paste .
Proof blanks are struck at least three times in succession with these remarkable dies to ensure the design appears crisp and clear on the flawless table of the finished coin .
COLOURED
There is a long history of coloured numismatic pieces . They became especially popular during Queen Victoria ’ s Golden Jubilee in 1887 , which prompted a huge demand for Royal memorabilia . Nineteenth century techniques saw enamel applied in layers , fired , and then ground down to create various shades .
In the spirit of this tradition , The Perth Mint has coloured certain coins since 1996 . The process employed has evolved over the years . Today we use advanced LED UV printers for exceptional results .