Any thoughts on this would be helpful as? I am unaware of the gem Stone. Its a 8kt yellow gold and i believe aquamarine?

[karlgbarnes]

 

[Bron357]

While Aquamarines are that tone, there is also the chance it is a lab grown gemstone. In the larger sizes they were very popular in cocktail rings in the 50s through 80s. Often lab spinel (which came is in many colours) or lab corrundum.
Other possible blue gems are topaz or even zircon.