About 15% of people in Germany have a nickel allergy and are sensitive to earrings with nickel content. Pure 24k gold is completely nickel-free and biocompatible. This means that it is harmless in case of nickel allergy. However, since it is very soft, jewelry is not made from it. Gold earrings are available with 18k gold, which is also a safe choice in most cases of nickel intolerance.