Small Asian Stela of Green Stone, Etched Legend...

~9 1/2" long, ~1 1/4" wide, ~5/8" thick; weight is ~12 1/4 oz.
The color is best shown in pic#5.
I would like to hear about what the stone may be, an' whether the script is old Japanese (as I suspect) or something else equally hard to translate. I have the sense that it's not an old thing, but cannot justify that except as a hunch. Posted here 'cause I'm without clue where else it may belong.
I haven't yet tried asking Asian Art forum for translation, but will if I strike out here. Thanks for lookin'!
Edit: I used a trick I learned from someone here: filled the engraving with silver-cream to greatly enhance the individual characters in the legend...Thanks!

 

It looks like Chinese cursive script to me, so paging @Kaiserpoo .

The stone could be bowenite. Bowenite is used a lot in China.
Not antique, but a nice chunk of stone.

 

Thank you, AJ! I'll look into bowenite...