It is proposed to describe blue phases by two order parameters: the st
andard alignment tensor field Q(alphabeta)(r) and a bond orientational
tensor order parameter of octahedral point group symmetry O(432). The
yet mysterious blue fog then emerges as a liquid of purely cubic bond
orientational order. In the transition from the cubic blue phases to
the blue fog the cubic space group symmetry is being reduced to its oc
tahedral factor group. Because of the new order parameter the O5(I432)
structure, which in all previous calculations proved most stable, but
never has been detected in experiment, is eliminated from the phase d
iagram.