How to Clean STERLING Silver Jewelry With GEMSTONES: Sterling silver contains anywhere between 92.5 and 94 percent pure silver; the rest of sterling silver consists of stronger metals, including zinc, copper and nickel. Pure silver is soft and pliable, while sterling silver is strong, less prone to tarnishing and usually less expensive. Clean, care for and store your sterling silver and gemstone jewelry correctly to prevent scratches or damage to the metal or stone.