Do not swim or shower while wearing gold-plated or silver jewellery, and remove rings when washing your hands. Chlorine, salt water and fresh water can damage precious metals and gemstones by dulling or eroding them. Gold and silver are particularly susceptible to damage from chlorine, which can permanently damage or discolour them. Soapy water when bathing and showering can also leave a thin film, which makes the metal seem dull. Some stones can also be quite porous (such as turquoise and lapis lazuli), which is why you shouldn’t leave these kinds of stones immersed in water for too long. Liquids and oils can seep into the gems through the tiny cracks between the crystals, causing permanent discolouration and damage. In addition, porous gems should not be worn to a beach or other hot, extreme environments.