Identifying a Vintage 10K Gold Ring with Emerald - Inscription Analysis

Question
my mother in laws great aunt has gave me her late husbands ring.he bought from mexico long ago it has a 10k stamp on it and looks like a 81 circled.but if turned up side down 18 circled.it has a beautiful green emerald.it looks like.i can see scratches on it and is a dark green stone in light looks very beautiful.the stone is set but can hear it shake like it is loose a little.it is scratched and looks a little chiped.what is it and what is the ingravings??

Answer
Questions concerning any markings or codes on jewelry are outside of my field of expertise and are best addressed to a jeweler.
From your description it is rather difficult to give you more information concerning the green stone. An emerald is the green variety of the mineral beryl(Be3Al2SiO36) and owes its green color to trace amounts of chromium and/or vanadium in its crystal structure. However, beryl minerals are very hard (Mohs hardness of 8) and are NOT easily scratched. Your description of scratches on the stone is therefore worrisome and point to something of lesser value, like green glass.
For assurance you may want to take the ring to a jeweler. They can test the ring quickly to give you a more accurate assessment.