  The magnetization steps of quintets, consisting of five identical magnetic
ions coupled by isotropic nearest neighbors antiferromagnetic exchange
interaction, in the hcp lattice, have been investigated. In that model there
are 17 types of quintets. The values of the magnetic field of the magnetization
steps of the quintets have been determined by numerical diagonalization of the
spin Hamiltonian, which is composed by the isotropic exchange and the Zeeman
interactions. The quintets are composed of individual spin $S$ = 1/2, 3/2 and
5/2. The contribution of the quintets for the effective concentration (or
technical saturation) as a function of the magnetic ions concentration was also
calculated.
