How old is this locket?

I'd say 1970s, probably made in India. Pretty.
There is verdigris, which is not usually seen on sterling silver, so you might want to test the silver fineness.

 

The green is from the silver solder

I think much newer than 70s

 

There seems to be wear on the back of the ring where the bail is attached. (4th picture down). Could that be a brassy color showing through...or maybe the top loop was an alloy for strength.

 

Maybe a repair? All in all it looks like a 70s Jaipur piece to me, also looking at the angle of the setting of the amethyst. There was more quality control in later years, even in the smaller workshops.

 

I believe what you are seeing is "firescale" from over heating while soldering,it brings copper to the surface.

 

Thanks, Hollyblue, you would be right about that. When I think about it, that isn't the spot to expect to see wear, it would be more likely at the top of the ring, rather than at the side.

 

JMHO.
with both sides to be seen the cut of the stone should say someting about the age.

 

There is nothing distinctive about the cut of the stone.The stone wasn't cut on an automated faceting machine,the facets don't "meet" and was probably cut in a back alley cutting shop in India the last 50+ years.

 

when I look at the style of 925, could it be Italian ? made in the narrow alleys near the Naples main station ?

 

Fid, you're making it sound very "Where Do You Go to My Lovely", with that line: "I remember the backstreet of Naples, two children begging in rags..."