Differentiating between authentic antique (defined by U.S. Customs as 100 years or more in age) or period jewelry and modern reproductions is a skill that is developed only through extensive experience and research. There are various clues that indicate an item’s age, and with time the student of antique and period jewelry learns to recognize many of these signs. For example, a certain kind of mechanical safety catch replaced the simple wire “C catch” around 1896 in Europe, and a few years later here in the United States. If the observer can be sure after thorough examination that a safety catch is original to the piece, and it is mechanical, the age of the item can be estimated within a very few year period. Other characteristics such as the delicacy or heaviness of the piece, the quality of workmanship, the cutting style of diamonds or other gemstones and the manner in which they are set, and hallmarks and date letters, all provide clues as to an item’s age and perhaps country of origin as well.