I purchased this on a trip to Boston, MA in 2010. All I know is that it is reportedly from the Ito period and was in someone's garden for many year. It was almost 50-75 pounds. It is lichenized.
Bought this from a fine art show in Boston
I believe your buddha is indeed made in Japan in late 19th century ( Edo Period ). It appears to be carved by hand in quite a soft stone type. It was alway's outside I figure and the rain and wind ( and sand ) and disintegrated a little. That, in my opinion, ads to the beauty. Lines are soft and it gives the buddha a ' mysterious look' Normally disintegration is not good for the value but I believe in this case the value will be the same as it were in original condition. I believe if your buddha came to auction you could expect is to make a price around the estimate.