Pearls, coral, opals, and lapis lazuli are among the gemstones that are considered semi-precious. According to the American Gem Trade Association, the term 'semi-precious' does not mean that these stones are inferior in quality or value and states that, "...all natural colored stones are rare and precious." Regular cleaning is part of taking care of semi-precious stones.
Clean opaque stones, such as opals, lapis lazuli, jade, turquoise and malachite, by wiping them with a moist cloth after each wearing. Avoid exposing these stones to soap and water; according to the International Colored Gemstone Association, these gemstones are basically rock-and not crystals from a single mineral-and could absorb the water and soap.
Clean organic gemstones like pearls, coral and amber by wiping them with a soft cloth after each wearing to remove dust and body oils from the gemstones. Protect them from exposure to hairspray, perfume or cosmetics, as the chemicals in these products can damage organic gemstones over time.
Protect opaque semi-precious gemstones by storing them in individual sections of a jewelry box, or in fabric pouches or wrapping them in pieces of soft fabric. This will prevent them from being scratched.
Clean transparent semi-precious gemstones. Fill a container-not the sink to avoid accidently losing the jewelry down the drain-and put a tiny amount of mild liquid soap in the water. Place the gemstones in the soapy water and allow them to soak.
Use a soft, non-metallic brush to brush the gemstone. Be careful not to brush vigorously as it could loosen settings.
Rinse the jewelry thoroughly under running water and lay it on a soft cloth to dry.
Separate gemstones from touching each other to prevent scratching. This can be done by placing them in separate sections within the jewelry box, using fabric pouches, or wrapping them in separate pieces of soft cloth.