Precious Metals

Royal Canadian Mint develops 'milk spot' fix

The Royal Canadian Mint has announced Mintshield, a new technology the RCM reports will minimize and even inhibit the future appearance of white spots on its Maple Leaf silver bullion coins.

Images courtesy of the Royal Canadian Mint.

The newest advance in silver bullion coin technology is something the Royal Canadian Mint hopes buyers never see.

The RCM announced Feb. 2 during the World Money Fair in Berlin the development of Mintshield, a proprietary new process that mint officials said reduces the occurrence of white spots on silver bullion coins. 

All 2018 Maple Leaf silver bullion coins, including the double-incuse coin and another special 30th anniversary design, incorporate this new surface protection technology. 

Invisible to the eye, Mintshield doesn’t alter a coin’s composition or purity and can be applied efficiently in a large-scale production environment, according to the RCM. RCM officials say that laboratory testing that simulates long-term use has demonstrated that Maple Leaf silver bullion coins treated with Mintshield successfully resist white spotting compared to all other silver bullion products in the market. As of 2018, all Maple Leaf silver bullion coins are enhanced with Mintshield surface protection.

White spots (also called “milk spots”) are surface discolorations that sometimes mar the appearance of silver bullion products. 

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Unlike tarnishing, which is a byproduct of oxidation, white spots don’t have a single predictable cause and this has complicated the search for an effective solution to the problem, which affects silver bullion coin producers all over the world. 

Mintshield technology is the latest advance for the RCM’s silver Maple Leaf program. 

The new technology joins features such as Bullion DNA anti-counterfeiting technology, laser micro-engraving and the Maple Leaf’s distinction as the first .9999 fine silver bullion coin.

“The Mint has a long history of revolutionizing the bullion industry with advances in purity and security, and Mintshield is yet another exciting step in that direction,” said Sandra Hanington, president and CEO of the RCM, in a press release.

RCM officials have not disclosed additional details about the use and application of the surface treatment. 

The development springs out of a decade-long commitment to research and development that includes the development of the aforementioned DNA technology, “Digital Nondestructive Analysis” that allows dealers to verify the authenticity of silver and gold bullion coins with a desktop machine linked to the RCM’s database. 

To learn more about Mintshield, visit a special page on the RCM's website

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