Materials Gemstone, Gold filled, Silver Gemstone: Opal Dimensions Necklace length: 18" (45 CM) Stone Color: White Stone Dimension : 3 MM to 5 MM (Approx.) Stone shape : Faceted Rondelle Necklace Length: 18" (45 CM) Carat Weight : 75 (Approx.) Silver Carat Weight: 3.8 Closure: Lobster claw 8 MM NOTE: The lobster claw is crafted in 925 sterling silver with gold plating.