Measuring 6mm, these earrings feature genuine Amethyst balls set into gold IP surgical steel. What is Gold IP? In traditional processes, the gold coating on the surface of the case can be rubbed off easily. Ion plating makes the gold plating more durable, more wear resistant, and also has a higher brightness. ... To this is added a gold coating, normally not exceeding 0.3 urn in thickness. To begin with, a layer of titanium nitride is added to the base surface of stainless steel. Additionally a final plating metal is added to the surface; the thickness of this layer is no more than 0.3 urn. ... Given its durability and chemical stability, ion plating is rightly called “permanent” coating.