Like all delicate and beautiful things in our lives, opals can be with us for a very, very long time – in fact they can be handed down to the next generation- if we treat them well. Opals contain water and their hardness ranges from 5 to 6.5 on the Mohs scale (Diamonds are 10 on the same scale). It is best to avoid harsh temperature changes, activities which would expose them to being scratched or broken (i.e. gardening) and prolonged exposure to heat or intense light as it could cause fracture lines. Last but not least, opals are vulnerable to harsh chemicals, in particular hydrofluoric acid and caustic alkaline solutions. Opals can be cleaned with warm, soapy water.