The jewellery that you wear in your piercing during healing time must be made of the EU nickel directive, 316L surgical grade stainless steel. Before jewellery can be used in a piercing it must be tested for nickel, ultrasonically cleaned to remove traces of dirt and polish, and then sterilised in an autoclave. Good piercers will keep stocks of jewellery that have gone through this process already, pre-packed in sterile packets.

The composition of the metal is very important. The jewellery you buy must be tested for nickel release. A European Union Directive has been passed that states that any metal used under the skin must not contain more than 0.05% nickel. This is very difficult to check for and just as difficult to police. Some low grade steels contain 10 times this amount of nickel and you can't tell by looking at it. Gold and silver are just as bad. 9ct gold is only 37.5% gold and tends to contain high levels of nickel. Nickel free gold is available from good piercers. Silver should never be used in piercings, as it will oxidise under the skin, causing a black substance (Silver oxide) to leak into the surrounding cells.

Jewellery can be changed one month later but the longer you leave the original jewellery in place the better the healing will be.

I do not advise that you leave your piercing without any jewellery inserted for any length of time as there is a strong chance that your piercing will close resulting in you having to have a re-pierce.

The jewellery that you use in your piercing is extremely important. Body jewellery is a specialist area and good body jewellery retailers tend to be where the good piercers are.

A good piercer will have an intimate knowledge of appropriate jewellery, composition of metals, appropriate anatomy (just because the jewellery suits your friend’s anatomy doesn't mean it will necessarily suit yours) and the reaction of the body to certain metals and trace elements that is gained by years of experience.
There is a large selection of jewellery available at N.P.N.G.