Clear gem care (precious stones like diamonds, rubies, sapphires and emeralds): You may
Clean these in an ultrasonic cleaner if you wish. However, if there is any other type of stone in the setting than you should NOT use the ultrasonic. You can also clean clear gems with a mild liquid detergent and a soft brush. Dry with a non abrasive lint free cloth.

Opaque gem care (semi precious stones like jade, turquoise and opals): Do not put these stones in an ultrasonic cleaner. This will damage the gems. Opaque gems are porous and will absorb cleansers and soap, which will build up inside the stones and discolor them over time. Clean by wiping with a soft damp cloth.

Organic gem care: (pearls, amber, corals, shell jewelry): Wipe with a soft damp cloth. Do not use chemicals. You can use ivory flakes to clean these gems. Opals are also susceptible to extreme temperatures. Too much heat and they will dry out. If you go outside into freezing weather with an opal the opal may crack. In both cases your opal is history, so be careful.

When dressing, always put on your makeup, perfume and hairspray first. Leave your jewelry for last. All of these substances can build up on your jewelry which would than require more frequent cleaning and also dullthe appearance of the gems. These substances can also out and out damage some gems, especially pearls.

Never wear jewelry of any type when cleaning around the house. The chemicals in household cleansers can damage the metal in your jewelry and will destroy some types of gemstones. Yes, you want to remove your rings before you wash your hands, as soap can damage porous stones, and hand or body lotion can also be harmful.

Silver care: silver tends to tarnish due to the metals it is alloyed with (usually its copper). Do not use toothpaste as a cleanser as it's to abrasive and will dull the finish over time with tiny scratches. You can clean with silver polish, with a no phosphate type of detergent, or by simply storing in anti tarnish bags or anti tarnish jewelry boxes. Do NOT
store pearls in this type of bag or box, however, as you will damage the pearl. You can also buy a more expensive alloy of silver and platinum which will not tarnish. Don't swim with jewelry on as the chlorine will pit the metal, and harm some types of stones.

Gold and Platinum care: Both metals can be cleaned in warm sudsy water, or take the jewelry to a jeweler for a steam cleaning. Buff the jewelry with a chamois or a soft cloth.
Gold is weakened and becomes brittle with exposure to chlorine, but platinum can stand up to most chemicals. Your best bet with jewelry is to look for a cleaner that is safe for both the metal and the gemstone-ask your jeweler.

Lastly, store your pieces separately to avoid the pieces scratching one another. There are many jewelry boxes that are set up to keep jewelry separate, but you can also place some pieces in individual soft bags. Doesn't cost a lot, either.