25 May 2012
Courtesy of Timothy Sherry. Lens cap nether-regions for scale.
He tells me that:
It’s from the “High Strain Zone” of the PFZ, a dextral shear zone that crosses the SA-Namibian border 28° 55.996’S, 19° 12.972’E. It is an ultramylonite, primarily quartz and feldspars; also chlorite and epidote if memory serves me.