Vintage 14k GF Opalescent & Black Onyx Necklace 1/20 14k GF 16.5" length

1/20 14k GF Estate Opalescent Stone and Black Onyx Necklace 16.5". In very nice preowned condition Estate find Necklace total length is 16.5 inches 1/20 14k yellow gold 1/20 means that there is one part gold to every 20 parts of other materials Appears to be opalite but cannot confirm Very beautiful necklace in person Please review all pictures for size and condition