Many stackers are familiar with the white spots—also called milk spots—that can appear on silver coins. Though these spots do not affect a coin’s precious metal content, they blemish the aesthetic appeal of bullion products. The Royal Canadian Mint underwent research and development to try to solve the problem of milk spots.
Earlier this month, the mint announced a new proprietary technology called Mintshield™ surface protection, designed to reduce the occurrence of white spots on silver coins. Sandra Hanington, the mint’s president and CEO, stated that “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.”
Aware of the unwanted surface discolorations, the Royal Canadian Mint set out to solve the issue of white spots four years ago. The first step was to discover what causes white spots, which are not like tarnishing or oxidation. The mint’s researchers collaborated with laboratories at a Canadian university and learned that white spots are unpredictable and can be caused by a number of factors, including reactions to contaminants during processing, handling, and storage. The irregularity of milk spots made it a challenge to find an effective solution. Yet after a lengthy R&D process, the mint developed Mintshield™ technology.
The Royal Canadian Mint believes that Mintshield™ surface protection, which is invisible to the eye and has no impact on the coin’s purity, provides a proven way to reduce white spots. How was this new technology proven? Mint employees subjected silver coins treated with Mintshield™ to accelerated testing—simulating long-term use—and was able to confirm that the surface protection would significantly reduce the appearance of white spots for years.
Further success was proven when the team confirmed that Mintshield™ could be applied efficiently in a large-scale production environment with consistent outcomes. Mintshield™ can be used on coins with a variety of textures and finishes.
The Royal Canadian Mint’s commitment to producing high-quality bullion products has led to proprietary Bullion DNA™ anti-counterfeiting technology, laser micro-engraving, and now Mintshield™ surface protection. Mintshield™ has been applied to all 2018 Silver Maple Leaf coins, and will continue to be applied to subsequent releases for the foreseeable future. Now you can buy Silver Maples—a worldwide favorite—without worrying about the development of milk spots!