I inherited a ring from my great grandmother and I'm wondering what the hallmarks mean and what the ring is worth. From left to right the hallmarks read R N, 15, 625. Then on the right side is a cross followed by a w in a box with the corners cut off.
The ring also has 5 amethyst on it.
Any help would be most appreciated.

[F]
Hello, You've got a very special treasure that your grandmother gave you. 625 is a hallmark for 15K Gold. Most common now is 14K Gold or 18K Gold. Your ring is quite vintage to have that grade of Gold stamped on it. I'm not sure what the other markings mean, perhaps they are the makers markings. One other thing you should know; 15K gold is almost never used in modern jewelry today! This is why You Ring is Special!:)
Sincerely
mswg3

Vintage I think it is Navajo made hallmark is KN or RN with Bull or Buffalo horns under the letters. Do you know who's hallmark this might be?

Vintage I think it is Navajo made hallmark is KN or RN with Bull or Buffalo horns under the letters. Do you know who's hallmark this might be?