Mortar - 18th Century French or 1900's Edwardian.

I'm trying to date this Mortar, using Google image search, the closest I can get is either early 1900's Edwardian or 18th Century French. I'm confident it is stone/granite, as opposed to Marble, but stand to be corrected?  It is very heavy at approx 17kgs, standing 8" in height and 11" in diameter.  

FYI - unfortunately it bears a hole in the centre as it has been used as a plant pot

Any guidance would be greatly appreciated,

thanks