A new K-V-Ba titanate, of the hollandite structural type, is described as a primary groundmass phase in mica-rich kimberlite. It forms interpenetrating twins of stellate crystals; these are opaque with reddish internal reflections and have the general composition A1.49B0.97C6.9O16, where A = K, Ba, B = V, Cr, Ce, Fe, Mn, Mg and C = Ti, Zr, Si. This mineral differs from previously described priderites and related phases by being relatively rich in V (V2O3 1.65-4.51%) and Ce (Ce2O3 0.70-1.76%) and in having a high K/Ba ratio; it crystallized at low P from a kimberlite rich in K, Ba, Ti, V and other incompatible elements and in the presence of kimzeyitic garnet and tetraferriphlogopite.-R.A.H.
