  We provide the indication of high flux of $^{40}$K geo-antineutrino and
geo-neutrino ($^{40}$K-geo-($\bar{\nu} + \nu$)) with Borexino Phase III data.
This result was obtained by introducing a new source of single events, namely
$^{40}$K-geo-($\bar{\nu} + \nu$) scattering on electrons, in multivariate fit
analysis of Borexino Phase III data. Simultaneously we obtained the count rates
of events from $^7$Be, $pep$ and CNO solar neutrinos. These count rates are
consistent with the prediction of the Low metallicity Sun model SSM B16-AGSS09.
MC pseudo-experiments showed that the case of High metallicity Sun and absence
of $^{40}$K-geo-($\bar{\nu} + \nu$) can not imitate the result of multivariate
fit analysis of Borexino Phase III data with introducing
$^{40}$K-geo-($\bar{\nu} + \nu$) events. We also provide arguments for the high
abundance of potassium in the Earth.
