These prohibit the retail of jewellery or products that come into skin contact and of more than 0.5 micrograms per square cm per week. They deal with prolonged contact and body invasive jewellery must have a nickel release rate of less 0.2 micrograms per square cm per week. There is not any requirement to label items (for practical reasons) so to be on the safe side always recommend buying silver jewellery or items made from non nickel materials such as shell or amber etc.
Nickel is a silver coloured element usually found in its metallic form. It is very resistant to corrosion and does not rust in the way that steel does hence it is often mixed with other metals to create a corrosive free alloy. Its is often used for the manufacture of coins, batteries and all manner of metal objects ranging from musical instruments to cutlery. It was also used widely in jewellery. The rings on the left are pure nickel and as you can see look like silver except their colour will change to a dull brown over time.
Some people can develop a hypersensitivity to Nickel particularly when the particles of nickel are dissolved by sweat and excess amounts of nickel enter the blood systems. This can lead to nasty skin reactions caused by nickel molecules binding to to the skin cells. Medical advice and assistance may be required in extreme cases. Nevertheless most people rarely realise how much nickel they encounter in their every day lives, such as using cutlery for eating. It is therefore crucial for a reaction to develop, that there is a prolonged exposure to nickel. A common example will be a rash developing around the belly from wearing a nickel plated belt buckle.
Nickel is mainly found in alloys of Iron or Sulphur. It is also found in meteorites. Its supply is being outstripped by demand so Nickel prices are now quite high and it can no longer be considered a cheap metal. Traditionally it was used in coinage however its expense has reduced that use.