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Ruthenium plating now in vogue

Enhanced one-ounce silver £2 Britannia (left) and ¥10 Panda (right) fully plated with ruthenium and then partially over-plated with gold. (Image courtesy www.powercoin.it)

Coins plated with black ruthenium have become popular collecting items in recent months. Apart from several dealerships that specialize in them, more and more varieties are turning up on eBay. The range is limited only by the imagination of those having access to ruthenium-plating technology.

The plating of coins is a natural progression from ruthenium plating of jewelery. Ruthenium provides a harder coating than rhodium and was developed to both protect jewelery and give it a trendy cool look. Matched black wedding rings, anybody?

A ruthenium coating can range from 0.25 to 1.0 microns thick and vary from gun-metal gray through to jet black. It can be applied directly to gold, platinum, palladium and silver.

None of the plated coins currently on offer are known to be a primary product of a major mint. Rather most, if not all, are private productions, the result of complete or partial plating of an existing coin. Pieces that have been selectively plated come commonly advertised as “ruthenium-enhanced.” In this respect they resemble the enameled coins of yesteryear.

And the plate shops have been running hot. Your favorite gold or silver coin is probably out there already, tastefully ruthenium-enhanced.

With many, but not all, a coin is first plated entirely in ruthenium black and then a main design element selectively over-plated in gold to leave it standing proud. The effect is to further heighten the enhancement.

How about a quarter, an American Eagle, a Bicentennial quarter, a Walking Liberty $1, a Indian Head Nickel, a JFK half dollar, a ¥10 Panda, a Canadian Superman $5, a Niuean Darth Vader silver $2 or, even, the full set of current U.S. Presidential dollars?

Sophisticated techniques have been recently introduced to bring an artistic finish to the plated portions of the design. Gold over-plated Standing Liberty and Britannia can be found wrapped in flaming auras. There is even a burning Maple Leaf.

Santa Muerte: one-ounce silver Mexican Libertad fully-plated with black ruthenium and then enhanced with artwork appropriate to Holy Death on the reverse. (Image courtesy www.melbournemintcoins.com.au)

One of the more spectacular productions is the transformation of the reverse of Mexico’s silver Libertads into a celebration of Santa Muerte.

For those with good chemical-handling skills and access to rudimentary electrochemical equipment the basic plating technique is relatively straightforward. Getting it right can be a bit trickier.

Walking Liberty’s fiery aura: 2014 U.S. one-ounce silver Eagle fully plated with ruthenium and then selectively over-plated with gold. (Image courtesy Power Coin www.powercoin.it)


The variation in coat color depends on the chemistry of the solution used. Several metal finishing companies offer a range of ready-to-use ruthenium plating solutions. These include one providing that extra-special matte-black appearance that is currently de rigueur for “coin enhancement.”

The technique can be viewed on YouTube. A search on “ruthenium plating” should produce at least three informative videos.

For those for whom ruthenium is something of a mystery, the silvery element is a member of the platinum group. It is derived as a byproduct of the processing of platinum ores with an annual production of from 12 to 20 tons. The current price is about $65 an ounce.

Like other members of the group it is unaffected by many chemicals. It is very hard and a major use in industry is the provision of wear-resistant electrical contacts.

Acknowledgements: Thanks to Power Coin and Melbourne Mint for supplying images and information.

 

This article was originally printed in World Coin News. >> Subscribe today.

 

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