925 Sterling Silver Unisex Blue Sapphire Round Cubic Zirconia Tennis Necklace 3mm 18 Inch - 20.0 Grams In Sterling Silver - FREE gift-ready jewelry box ::: [ Potential Enhancement Methods: cubic zirconia ] - Synthetic. Some are covered with a product that makes the stone more durable. ::: [ Care and Handling: cubic zirconia ] - Clean with warm soapy water and a soft cloth. ::: ::: [ Potential Enhancement Methods: blue sapphire ] - Usually heated to improve appearance. Occasionally irradiated. Commonly diffused along with heat application to create different colors. Yellow sapphire is always diffused. ::: [ Care and Handling: blue sapphire ] - Avoid strong detergents, heat, pressure and ultrasonic cleaner or steamer. Avoid re-polishing or re-cutting of the stone. Color may fade in light or with heat. Clean with warm soapy water and a soft brush or cloth. :::