craziibaby33 , it's a tough call to make from only images .
railman44s' is the best suggestion .
My best guess is that your ring is .925 silver , for the most part .
I can't really tell for sure from the images , but I suppose that there could be elements of your ring done in 18k gold .
The ring appears to be cast , rather than made from a billet , so I'd look for gold elements that were soldered to the silver (they wouldn't be cast together) ... 18k is pretty soft stuff & not that much in use for alot of jewelry of the type you have .
The '18k' stamp would be incorrect , for any gold-plated item .
I am also guessing that it was made by an independent silversmith/jewelry-maker/artist .
The stampings are a bit odd & confusing , but the jeweler can get it straightened out for you .
I have seen other items stamped/hallmarked like yours , some real , some fake .
There's a whole list of semi-precious stones that it could be crafted with .
To my mind , the important thing is "if you like it , wear it" .