It is a piece of anthracite coal.
And you misread the '8': it's an "A", because that organic sedimentary rock was found in Alberta. Must be from the Pre-Coal-Creek-Rebellion-Period, because later only rainbow colours for used for the 'A'.
Mon 11 Apr, 2016 04:19 am
It's about six inches in diameter, black, and there is a white number "8" floating around on one side.
Boy, that's a tough one, we'll need a photo. Ask dalehileman for instructions on how to upload one