Overlapping area represents the amount of risk that can be diversified away by holding Orestone Mining Corp and Parex Resources Inc in the same portfolio assuming nothing else is changed. The correlation between historical prices or returns on Parex Resources and Orestone Mining is a relative statistical measure of the degree to which these equity instruments tend to move together. The correlation coefficient measures the extent to which returns on Orestone Mining Corp are associated (or correlated) with Parex Resources. Values of the correlation coefficient range from -1 to +1, where. The correlation of zero (0) is possible when the price movement of Parex Resources has no effect on the direction of Orestone Mining i.e. Orestone Mining and Parex Resources go up and down completely randomly.