  We consider the problem of exact experimental determination of the boundaries
of Stability Zones for magneto-conductivity in normal metals in the space of
directions of $\, {\bf B} \, $. As can be shown, this problem turns out to be
nontrivial since the exact boundaries of Stability Zones are in fact
unobservable in direct measurements of conductivity. However, this problem can
be effectively solved with the aid of the study of oscillation phenomena
(cyclotron resonance, quantum oscillations) in normal metals, which reveal a
singular behavior on the mathematical boundary of a Stability Zone.
