I paid close attention to their conversation, but pretended to be examining the many pieces of jewelry for sale in the display cases. Eventually it was determined the gold chain was real, 18k, and quite heavy at 5 ounces and they had negotiated a price that was roughly 70% of the current market price for gold which was actually pretty good considering 55 to 75% of total value was common for gold intended to be melted down.
https://www.pawnamerica.com/blog/how-much-is-a-14k-gold-necklace-worth-at-a-pawn-shop