Care of Semi-precious and precious stones
Hardness
Mohs scale of hardness was developed by a German mineralogist in 1812, it's not a scientifically accurate scale but is functional (good enough) and still used by jewellers to classify stones. Low numbers indicate softness and high numbers hardness so higher number stones will scratch lower number stones. Here is a list of the most common stones and their hardness. Sterling silver (and Gold) has a hardness of about 2.75 so you can imagine how easy it is to scratch if you are not careful.
Obviously the above chart is one of the main reasons why jewellery needs to be kept seperate and boxed/wrapped. If you allow jewellery of different hardnesses to rub against each other in a large jewellery box then you will get scratches. In particular, great care needs to be taken of pearls and amber items. Stones above 7 on the scale are pretty resilient and OK for everyday wear but remember that their gold and silver settings only have hardnesses of just above 3.5, so if you want to keep that surface shiny you need to be careful. Although, there is a charm about the patina of a well worn piece of jewellery.
Dyed and Treated Stones
A particular issue with modern semi-precious stones is that many of them are colour enhanced through heat treament and dyeing. If you think that a stone might be dyed (its colour is more vivid than "natural") then you need to be careful of leaving it in the sunlight (sunlight bleaches) or of allowing it to come into contact with household cleaners and bleaches. As a general rule it is best to keep anything other than diamonds safely on a shelf while you are cleaning and doing housework.
Care of Silver
As mentioned above, silver (and gold) are fairly soft materials and if you want to preserve the high polish the jeweller spent ages achieving you will need to take care. Polished silver is the most reflective of all metals, more reflective than gold or platinum. Badly scratched silver can always be buffed up to it's former brilliance by a silversmith. Tarnish is caused by humdity and chemicals in the atmosphere (often from food and cooking) and oils from the hands. Always put jewellery on AFTER applying hairspray and perfume.
Basic care of silver is to wrap it in anti-tarnish tissue and to keep it in a sealed plastic bag when it is not being worn. If you can get hold of it, then the small bags of silica gel can be put in the bags and will help a great deal. There are also commercial anti-tarnish strips available. Do no store silver with rubber bands, newspaper or cling film as all have chemicals in them that can react with the surface of the silver and cause problems that a silversmith will need to polish out for you.
Ideally, if you wash and dry your silver with a phosphate free soap (look at the Ecover or other environmentally friendly range of products for a suitable soap) after wearing it then store it properly, tarnish will not be a problem.
Light tarnish can just be removed with a soft, pure cotton cloth and a bit of elbow grease or with a gentle wash as above. If the item is more heavily tarnished then you will need a proprietary silver polish such as that made by Duraglit (called Silvo in the UK) which has an anti-tarnish formulation. When polishing remember that these products are abrasive (they take a thin layer of silver off when you polish with them) so how you polish is important. Apply very small amounts of polish in a straight motion, never use a circular motion as that can produced a scratched "halo" effect. Polish off with a soft cotton cloth and make sure you have removed all the polish.
If the object you are polishing has soft stones in it (Pearls, Amber etc) then use a cotton bud very carefully on parts of the item away from the stone, again only use a straight motion and make sure all polish is removed when you have finished.
If you have silver that needs polishing/cleaning and you want some advice or help please mailto:helen@helenquenet.co.uk
