Unusual wood &turquoise ring

Hello all, we have this strange ring with wood and turquoise. There is no maker's mark from what we can tell, but it has engraving on the inside. There is a hole on the back where the makers mark could have been, but we are not certain. Any info on style, origin, or period would be greatly appreciated!

 

Hi.
I have a key chain that looks almost identical. It is turquoise and petrified wood. The only marking is a SST.
greg

 

They made wood jewelry for a while in the 50s; it was a fashion thing. There's writing on the inside, but it's only half visible from here and upside-down into the bargain. It looks like some sort of artisan piece.

 

I see letters in the middle of the inside design like evelyb. Is this what you meant with "engraving on the inside?" Here's is the writing rotated and enlarged. I still not sure what it is. It could be Annie, Arnie, ??nute, etc...

--- Susan

 

What does the inside of the bottom of the shank look like?The inside isn't engraved,it's chased and the ring looks like it was made from a patterned scrap of something else.

 

There's something in there. It could be Arnie too.

 

Mexican maybe?

http://www.925-1000.com/mexican_marks.html