I only vaguely remember some of the details of the plot, but it was about this magic stone that was black and white, and it got shattered into the two black and white pieces. The bad guy used the black piece to do his nefarious deeds (I cannot recall what he did), and in the end the good guys prevail (obviously) and put the two pieces back together. Sorry that there aren't many details, but this was over 18 years. I watched it on VHS. Any ideas?