Argentium Sterling Silver makes it possible for people like us to trust silver again. It is nickel-free and safe to wear if you have a nickel allergy. But it has additional qualities that make it a true top-choice contender for fine jewelry. It contains even more pure silver than standard Sterling silver (93.5%), it shines brighter than platinum, and resists tarnish. If all this isn’t enough, it is made entirely of recycled silver, making it one of the most environmentally friendly options in jewelry.

The 1% of germanium in Argentium that acts as the hardener in the metal. This not only has the very practical effect of making the metal tarnish resistant, but also eliminates the uncertainly about what hardener is used in it. 5.5% of this alloy is pure copper, which is soft and tarnish-prone on its own (like pure silver is) but makes the silver harder and more durable.

For all of its admirable traits, standard Sterling Silver can be a little unpredictable as far as nickel content goes. in addition to silver and copper, it also contains a third, often unidentified metal which hardens the alloy. There are a few things it can be, but that metal can be nickel, and can trigger a nickel allergy rash in some people. 

Argentium has some similar properties to standard Sterling Silver, however there are a few unique things about its care that may be unfamiliar to you. 
Here are a few things that might be helpful to know:

First of all, you will rarely need to polish your Argentium Sterling Silver. Sometimes people who have always used Standard Sterling have a hard time adapting to this new reality.
Do not use cleaners intended for use with standard Sterling Silver. If you feel that your jewelry needs cleaning, You can clean it in warm water with mild soap solution, then pat it dry gently with a soft cloth. It can be immersed in water if there are no soft stones or pearls in the piece. Do not handle it with an abrasive cloth or sharp tools.
You can also purchase a polishing cloth that is intended for Argentium Sterling Silver, Goddard’s Silver Polishing Cloth. This is generally available at retail outlets, and is a soft cloth that will last for many uses.

It is best to store Argentium individually in a soft cloth or plastic pouch, or jewelry box. This will further minimize the chance of your jewelry tarnishing, and prevents it from getting scratched.

Also (weird but true), you should not store your Argentium near rubber bands. Sulfur is used in the making of rubber bands, and the residual sulfur present is enough to cause the Argentium to tarnish too. Just keep the jewelry in its own little pouch or box and you’ll be fine.

General jewelry care rules apply of course - don’t expose it to household chemicals, pool water, lotion, cosmetics, hairspray, tornadoes, fire, or flood.  

You may be interested to know that I heat-treat all of the Argentium I use in jewelry creation now to enhance the tarnish resistant properties. The heat causes the Germanium to “rise” to the top of the metal, therefore speeding up the formation of the protective layer which inhibits tarnish from forming. I also (often) pretreat it by tumbling it, improving its hardness.