Mother of pearl is made from the inner lining of different mollusk shells, pearl oysters, freshwater pearl mussels and abalone. The iridescent inner lining of the mollusk, called nacre, provides protection from parasites and bacteria.They create this inner lining in the same way they create 
pearls. It is a layered combination of calcium carbonate crystals, silk proteins and other materials. The layers are what produce the different wavelengths of light that cause the colors to change when viewed at different angles.
Mother of pearl is a popular jewelry element because of its iridescent appearance and affordable price. While a pearl and mother of pearl are both made of nacre, they are not the same. When making mother of pearl, beads are cut from natural sea shells then dipped in a solution containing their iridescent mother of pearl powder along with coloring agents and binders. Once dry, the mother of pearl is strung together in sets. However, the nacre layer is thinner than you would find on real pearls so they are somewhat more delicate.
You can test for the authenticity of a mother of pearl bead with this simple test: carefully, tap it against your teeth. It will "click," whereas a plastic bead would make a muted sound.
Although Mother of Pearl is an affordable jewelry option, proper care is still required to protect your piece. To do this you must keep it away from direct sunlight, strong sources of heat or very
dry atmospheres. If the Mother of Pearl becomes dry, the surfaces will crack and become less resistant to wear and tear. Also, be sure to remove your pearls when applying cosmetics and perfumes.
To avoid the risk of discoloration and yellowing you must properly care for your jewelry. Skin conditions can sometimes produce acidity that is harmful to pearls.Make sure it is the last thing you put on when dressing. Keep your jewelry clean as perfumes, suntan lotion, humidity and perspiration all affect its look and longevity.
PROPER CLEANING
It is best not to clean mother of pearl jewelry with harsh cleaners, strong abrasives or alcohol as they will destroy the original color. Never clean your pearls in an ultrasonic cleaner or use detergent, baking soda or ammonia based products.
This will remove any skin oils or dirt without scratching the soft delicate surface. If wet, lay them
on a soft cloth todry before storing - do not hang them to dry. If they are strung on silk be aware that silk shrinks if it gets wet. If you care for them properly they will last a long time. If your necklace is particularly dirty take it to a jeweler or use only recommended jewelry cleaners.
NICKEL AND COPPER ALLERGIES
Most jewelry contains alloys. Allergic reactions to metals such as nickel or copper can cause a chemical reaction frequently changing the color of your jewelry. But because pearls are generally hypoallergenic, reactions such as these, are rare.
