Onyx; 14K yellow gold; 18-20" adjustable length; pendant: 0.33"L; Lobster clasp; Almost all gemstones and blue and black diamonds have been treated to enhance their beauty and require special care; Photo may have been enlarged and/or enhanced; All gemstone carat weights (tcw) are approximate; variance may be 0.05 carat.; Opal is the October birthstone.; Imported