Seeking info about this cygnet ring I found (and damaged) while detecting for nuggets. The band is stamped AUSTRALIAN GOLD but has no makers mark or purity. I think it was made in the 1800s. XRF test gave a reading of 16 karat. Does anyone know if the AUSTRALIAN GOLD stamp is/was commonly used? Does it only identify what it is made from or does it also act as a reference to its purity or an industry standard?