That is a big chunk of beautiful material that prehistoric people in my neck of the woods would have loved to have used. If it was found on a known site, or if that material is not commonly found in that form in your area, then I would have no problem believing it could have been intended to be used as a core for prehistoric tool making. We probably won't be able to see the differences in patina that you can see while holding it in person, and it doesn't appear to have had typical flakes removed from it to be an expended core. What can you tell us about the situation in which it was found?
Found this the other day, has that "Paleo Sheen" handled shine to it , its not wet in pics. Found quite a few peices in area that look as if theres 100's-1,000's of years between some of the knapp impacts, as in found, knapped,lost, found years & years later then knapped again. This (Clovis) 
core shows those signs too, but what would I know, i wasn't there!... View attachment 1654511unfortunatly.
ke really, but i do have a feeling about this site , i had it registered with the state in museum in harrisburg, after long emails ,pics ect. back and fourth with Dr.Kurt Carr the top dog at the museum, and a few other arkis , led me to bring all my finds from site to Meadowcroft rock shelter when theyre all there, except... Kurt! anyway.. its a bring your finds weekend, needless to say the jaws were dropping when they seen the 8ft bed of my truck FULL! especially when they saw the 100pounder lol . My actuall site is maybe 25x25 yrds, few pics from it
