It is characterised by a low mosaic spread angle, meaning that the individual graphite crystallites are well aligned with each other.
[1] The method used to produce HOPG is based on the process used to make pyrolytic graphite, but with additional tensile stress in the basal-plane direction.
The "stress recrystallization" of graphite was first described by L. C. F. Blackman and Alfred Ubbelohde in 1962.
[2] The diameters of the individual crystallites in HOPG are typically in the range 1–10 μm.
[3] HOPG is used in x-ray optics as a monochromator and in scanning probe microscopy as a substrate and for magnification calibration.