Your Weta silver jewellery has been proudly made in New Zealand of finest sterling silver. All sterling silver contains about 7.5% of copper alloyed with pure silver to make the resulting alloy strong enough for jewellery purposes. Sterling silver is the traditional standard for silver jewellery and has many hundreds of years of use around the world.
What is Tarnish?
From Wikipedia, the free encyclopedia:
Tarnish is a thin layer of corrosion that forms over copper, brass, silver, aluminum, and other similar metals as their outermost layer undergoes a chemical reaction. Tarnish does not always result from the sole effects of oxygen in the air. For example, silver needs hydrogen sulfide to tarnish; it does not tarnish with only oxygen. It often appears as a dull, gray or black film or coating over metal. Tarnish is a surface phenomenon, that is self-limiting unlike rust. Only the top few layers of the metal react, and the layer of tarnish seals and protects the underlying layers from reacting.
Tarnish actually preserves the underlying metal in outdoor use and is called patina. The formation of patina is necessary in applications such as copper roofing, and outdoor copper, bronze, and brass statues and fittings.
Causes
Sterling silver contains both pure silver and pure copper and therefore will be subject to tarnish from both oxygen and hydrogen sulphide in different situations.
In high sulphide atmosphere environments such as industrial areas, geothermal areas and thermal hot springs (sulphur springs etc) silver may tarnish and this can be dramatic when sulphur (which is good for the skin but not for silver) transpires through the skin.
Silver may also tarnish in contact with egg yolks in food and mayonnaise, and with certain hair and makeup chemicals. Apart from outside influences, each individual's skin chemistry is unique and varying constantly. The skin is the body's largest organ and its acidity and moisture levels change in response to humidity, diet, vitamin and prescription medicine consumption, exercise and natural perspiration.
The above is not an exhaustive list but serves to indicate that there can be many causes of tarnish and that it might be difficult to pinpoint an exact cause in a particular case.
Prevention
Having mentioned all the possible causes of tarnish on silver we should not generally be overly concerned. In most cases, naturally occurring tarnish on silver jewellery is kept under control by the self-polishing action of the jewellery wearing on a person's body skin or fingers and often no special actions are every required to keep the piece looking 'silver'.
For moderate tarnish, of the sort that might build up on a piece not worn for some time for example, use of polishing cloths impregnated with chemical cleaning agents will normally restore silver's shine and polish.
For heavier more stubborn to remove tarnish we recommend use of a proprietary silver cleaning dip solution. The item is typically dipped for only a few seconds into a liquid and then rinsed in warm water and dried. This normally removes even heavy tarnish and use of a polishing cloth then can restore shine. The brands vary from country to country, but you will find them on your supermarket shelf or in a DIY or home improvement store.
We typically find that if people are having problems with tarnish that it is typically an initial reaction and if they go through a few cycles of cleaning and polishing, drying and making sure their skin is dry before they put silver on, that eventually everything beds in and the problem doesn't persist.
We understand how concerning a tarnishing reaction can be and hope these notes are useful to you.