Some jewellery consists of a material that is covered with a layer that gives a certain color or shine to the piece. Colors can be given to jewelry that cannot be obtained in any other way, such as black or red, or a piece of jewelry can be given a color without immediately making the price very high, such as gold colour. PVD coatings and gilded or gold plated are the most famous variants.
The biggest disadvantages of this type of jewelry are that it’s often unknown what that layer is made of. A good piercer only wants to pierce you with materials that contain nothing that could be harmful to your health or that irritates the skin. Furthermore, a coating always comes loose, the only question is when. If this happens while the jewelry is in a fresh piercing, it can cause quite a few problems. There is also the question of what material is underneath that coating. If that is a material that also contains harmful or irritating substances they might cause you irritation or other complications.
Jewelry with a coating is therefore only suitable for fully healed piercings.