A pearl can become tarnished and crack if it is exposed to a too strong source of heat or if it is kept for years under too dry conditions, such as in sealed plastic sack or in a safe.
Your pearls require the same attention as your other jewels. Here some simple advise to follow: Your pearls can be damaged in contact with the cosmetics, the perfumes, the lacquers and natural oils for the body. Please finish your skincare before carrying your pearls. In order to preserve their gloss, wipe regularly with a slightly wet soft fabric. In your jewel case, separate your pearls from your other precious stones in order to avoid any scratch.