Help with Australian Makers Mark - Ring

by Kelly
(Australia)

I inherited a ring from my mother, its a 925 sterling silver ring with three pink stones and an etched sunburst design around the stones. But what i want to know is who's the marker? I'm from Australia so that makes it hard to find any info.

I'm pretty sure its from the 70s or 80s, so its not an antique but the markers mark that's on the inside of the ring is a Heart pierced with an arrow and inside the heart is an NY or MY. Any ideas?

Thank you if you can help!
Kelly