Mystery Pink Granite Sphere

I found this a couple months ago near Jolon, California. Only a small portion was aboveground and the rest was below. I thought it was strange because i had never seen pink granite in California before. This looks like the pink granite of Bar Harbor, Maine - a very long ways away. I couldn't believe when i unearthed it, that it was so spherical! i've never found a natural stone which was so round! it's very unusual. I found some broken arrowheads in the same area - on a friend's ranch. This piece is very heavy, although i'm not all that good at judging and i don't have a scale large enough to weigh it. - probably 8 lbs or so. I thought i had lost it somehow, but it was found when one of my helpers cleaned my truck the other day. It really made my day to re-discover it! Apparently there is a pink granite mine down in San Bernardino, but that's a very long ways away. I can only assume that it is an artifact, but who knows?