Unlike diamonds, which are the hardest stones in the world, opals are delicate and soft. They are extremely easy to damage and scratch, either while wearing or cleaning, so you should always take care when opals are around. The surface of the opal should not rub against anything rough or pointed, so store it by itself, preferably wrapped in a soft cloth. Any materials you use to clean an opal should also be gentle and soft.
To clean your opal, the best choice is to grab a soft tissue or dry piece of silk. This will be easy on your precious stone and won't risk any damage or scratches. If your opal is especially dirty, you can use a simple solution of warm water and mild soap. Apply it either with your fingers alone or with an extremely soft, gentle toothbrush. Look for a baby toothbrush or one that is very old and worn down.
How to Clean
If you are using a dry tissue or silk, clean by gently rubbing across the surface of the opal. Bring the silk down around the sides as well and move in a slow, circular motion to leave a polished shine. If you are using a warm water solution, be extremely careful that the water is not hot. Hot water can greatly damage your opal, so if you are not sure, it is best to let the water cool slightly before using it. Cool water works to clean an opal, as well. Dip your fingers or toothbrush in the water and rub slowly and gently across the surface of the gem, focusing specifically on dirty spots. Rub with a clean tissue to dry.
Things to Avoid While Wearing an Opal
If you treat your opal right, it will be challenging to get it dirty in the first place. Opals should never be worn while playing rough sports or engaging in physical activities where they can get banged around. Don't wear your opal ring while washing dishes or showering because the sudden changes in temperature and hot water can ruin the gem. It's best that you wear your opal jewelry only occasionally to preserve its beauty and never choose an opal as an engagement ring. A diamond can stand up to accidental bangs and general wear and tear, but an opal can't.