I have one of them put up somewhere , probably in a box like so many of the bottles I have . I dug it in Cincinnati a good many years ago . Always thought the cap made it a neat bottle , a keeper in my opinion . The roller looks to be made of concrete to me . Picture are deceiving at times though .
That IS a granite roller, and it probably has a fair amount of value as a decorative stone.
My friend deals in suchlike stone, and I bet he could sell that to a high-end landscaper for a couple hundred bucks.
If that is granite , I would say you are right about it being worth a bit Richard . Like I said , pictures are deceiving for my eyes at times . I have seen many of these rollers over the years , had one that looked just about like this one at one time , but the roller was poured out of concrete .