» If you don't keep your diamond clean, especially at the back, it reduces its ability to return light to the eye.

To clean it at home, use some off-the-shelf jewellery cleaner and brush it on the diamond. Rinse it off and let it dry. Use an old make-up brush for the hard-to-reach angles.

You can also make your own solution - one part ammonia, four parts hot water - and simply soak your diamond in that.

Do the above for rubies and sapphires too.

» Emeralds are the most delicate of the four major stones. They should be gently cleaned with very mild soap and water. Never steam-clean. It's best for emeralds to be cleaned by your merchant.

» Pearls are organic and can become stained because their surface is porous. If you're going to put on your pearls, put on your fragrance and let it dry before you put them on. Otherwise, you could damage them. The rule of thumb is to put on your cosmetics and do your jewellery last.

To clean pearls, immerse the whole strand in a soapy solution (not too soapy and not a thick soap) and then clean them.

Let the pearls dry before you put them away. Simply pat them dry with a cloth and leave them by the window for a day or two. This will also ensure that the drill holes dry completely. Otherwise the silk within will rot.

Never dry pearls under a lamp or with a hairdryer.

This article was first published in Urban, The Straits Times on Apr 24, 2008.