A very old Pike stone-Lake Superior

[Steel]

I just got this in the mail today and it seems to be around a 300 grit fine sandstone. Research has brought up little but some old archives (1880-1895) talk about this stone coming from Ohio (despite the name of Lake Superior) and they say it is similiar to a Labrador stone (not labradorite). I have been looking for a natural stone to remove chips and what not and sandstone proper has been too rough to use on razors. This one seems to fit the bill. Time will tell. I figured I would share it here since there is little info on the web and no pictures that I have been able to come up with.