The use of 925 sterling silver may cause your finger to become green (or black). It is less prevalent than with costume jewelry, but it is nonetheless conceivable. There's no way to know until you put it on, and it may alter over time. Silver is commonly found in lead, copper, and cobalt arsenide ores, and it is also frequently related with gold in nature. The majority of silver is extracted as a byproduct from ores mined and processed to get these other metals.