Rollstone Boulder | |
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  Rollstone Boulder | |
| Coordinates: 42°35′12″N 71°48′21″W / 42.58668°N 71.80595°W | |
| Location | Fitchburg, Massachusetts |
| Formed by | porphyritic granite |
| Geology | glacial erratic |
The Rollstone Boulder is a ten-foot-tall, 110-ton porphyritic granite glacial erratic located on a traffic island in downtown Fitchburg, Massachusetts. The boulder was exploded at its original location at the summit of Rollstone Hill and then reassembled near Fitchburg's Upper Common in 1929 from the pieces.