Details: - 14K Gold Filled Ball chain - 18K Gold Filled Herringbone chain. Width: 4mm - Stone size: Approx. 10mm x 14mm - Stone material: Synthetic Black Onyx - Stone setting material: 18K Gold Plated over brass We have two necklace length options: 1. 14" Snake/Herringbone Chain with 1" extender (up to 15 inches) 16" Ball chain with 1" extender (up to 17 inches) 2. 16" Snake/Herringbone Chain with 1" extender (up to 17 inches) 18" Ball chain with 1" extender (up to 19 inches) Each item is individually placed on our MIKUKUMI leather card & cotton pouch. What is Gold Filled? Gold filled is a metal composed of a solid layer of gold that is bonded to a core base metal through heat and pressure. Gold filled jewelry will not wear off over time, and if taken care of properly it can last a lifetime. Gold filled items are indistinguishable externally from solid gold but costs significantly less because of its base metal core. It differs significantly from gold plated. Gold plate consists of a thin, microscopic layer of gold that will wear off over time. The gold content on gold filled items is around 15 times thicker than gold plated jewelry. Unlike gold plated jewelry, it's safe to get your gold filled jewelry wet. You can wear it to bed, in the shower, and while you exercise. We would generally suggest avoiding pools and hot tubs for any type of jewelry.