Quantification of the abrasive wear of a gold wedding ring

Abstract

Pieces of gold jewellery, especially rings, are known to suffer continuous abrasion during the time they are worn. This fact causes troubles in chemical analyses, because analytical methods that are sensitive in the determination of gold, especially Neutron Activation Analysis (NAA), are often faced with contamination of gold from human fingers. Since no other piece of jewellery is worn more often and regularly than wedding rings, quantification of the abrasion of a wedding ring is necessary. In this study, the abrasion of an 18 carat gold wedding ring was quantified by weighing the ring weekly over the period of one year. The composition of the ring (75 Au - 15 Ag - 10 Cu) was determined using NAA. In one year, the ring lost 6.15 mg (0.39 mm3) 18 carat gold due to abrasive wear. The highest abrasion could be observed in the course of vacation on the beach, where obviously the friction with sand increased the abrasion. Gardening and skiing also result in increased abrasive wear. However, the author suggests not wearing rings in analytical laboratories to avoid this contamination.