is a boron mineral found as microscopic inclusions in native arsenic from the Bor pit.
In different limestone-dolomite associations the boron-rich minerals harkerite, ludwigite
and fluoborite have been identified, though not together.
The first [ILLUSTRATION FOR FIGURE 12 OMITTED] was given the now discredited name "breislakite." The name is still used by local collectors, as "breislakite" is now known to be either ludwigite
or vonsenite, the two occurring together and even as mixed crystals at this locality, and being indistinguishable without chemical analysis.
It has also been found in drill cores as a mantle about ludwigite
grains from the Aldan Shield in eastern Siberia (Grew et al., 1991b).