For the Ni dataset, the input data exhibits a correlation length of about 7.5 d • Ω for both the semivariogram and gradient methods. For the Fe dataset, we observe 6.2665 d • Ω for the semivariogram method and 8.3073 d • Ω for the gradient method, the average of the two being 7.3 d • Ω . Thus both datasets seem to have correlation lengths of about 7.5 d • Ω . This is significant. For symmetric tilt GBs, the octonion distance metric corresponds to half of the difference in misorientation angles. That means that in the more traditional units of degrees of misorientation difference the observed correlation lengths are very close to 15 • , which is the traditional low-angle GB threshold. Thus, the traditional 15 • threshold appears to hold (on average) more generally than just for differentiating low-and high-angle GBs. Rather we find that on average, GBs that are within 15 • (7.5 d • Ω ) will have well correlated energies regardless of their misorientations or GB planes (i.e. it is not restricted to symmetric tilt GBs, but holds across the entire GB character space).