Silver has been used since the Middle Age and is popular for its white color, relative hardness that is higher than gold’s, chemical constancy, good workability and high glance. Today’s jewelry uses composition of silver, in Czech is allowed with hall-mark 925 and that means 92.5% of silver in a composition with copper. The top is sometimes covered with a tiny layer of rhodium or clean silver to increase the glance. Wearing of silver jewelry is minimally difficult to take care of. It may be damaged when it’s hit or touches chemically aggressive material. But not many people know that the most dangerous materials are mainly perfumes and cosmetic creams. The biggest disaster is hydrogen sulfide, which stays behind oxidation (blackening) of jewelry and there doesn’t have to be plenty of it in the air. Fortunately every experienced jeweler knows how to fix it.