Argentina gold ring.

[Ray1962]

I’m hoping someone will be able to give me some information about a gold ring I have.I’ve tried to photograph the hallmarks but it’s difficult,my camera is not the best so I will describe it as much as I can.The markings are a rectangle box with 750 inside,on the right of that is D90 and below are two words Industria Argentina,there is also a date inscribed of 4-3-70.Im told ring was given to a woman in the USA as a gift in the 1970’s.What I’m hoping to find out is if it’s 18ct gold and where it was made and by whom,I’m not sure if the D90 represents the maker ??? Any idea what the image on the ring is,initials maybe ? I’m stumped.
Thanks
Ray