Pyrite can be one of the major constituents of organic-rich mudrocks with its weight concentrations as high as 40 wt% . Pyrite still remains embedded in the demineralized sample after successive physical and chemical treatments of the organic-rich mudrocks . One of the effective methods to eliminate pyrite is to use acidic CrCl2 solution . However, this procedure produces toxic H2S. propose a safer density separation method using ZnBr2 solution to eliminate pyrite.