Gold Over Sterling Silver 925 Green Turquoise Slide Pendant Necklace 18"

This Beautiful Necklace is Gold Over Sterling Silver 925. The necklace measures 18 inches long. The slide pendant measures 1 inch wide and is Beautiful with a Turquoise stone. The case has shown some wear and tear but it does not affect the necklace The case said Black Hill Gold but I haven’t been able to Authenticate it so that a ????