  We present a direct observation of a coherent spin precession of an
individual Mn$^{2+}$ ion, having both electronic and nuclear spins equal to
5/2, embedded in a CdTe quantum dot and placed in magnetic field. The spin
state evolution is probed in a time-resolved pump-probe measurement of
absorption of the single dot. The experiment reveals subtle details of the
large-spin coherent dynamics, such as non-sinusoidal evolution of states
occupation, and beatings caused by the strain-induced differences in energy
levels separation. Sensitivity of the large-spin impurity on the crystal strain
opens the possibility of using it as a local strain probe.
