In this paper the relationships existing among the Boolean (j-algebra generated by the open central projections of the enveloping von Neumann algebra & of a C*-algebra J^ the Borel structure induced by a natural topology on the quasispectrum of sf, and the type of sf are discussed. The natural topology is the hull-kernel topology. It is shown that this topology is induced by the open central projections and is the quotient topology of the factor states of SZ (with the relativized i0*-topology)

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... nder the relation of quasi-equivalence. The Borel field is shown to be Borel isomorphic with the Boolean cr-algebra multiplied by the least upper bound of all minimal central projections. Finally, it is shown that ^ is GCR if and only if the Boolean σ-algebra (resp. algebra) contains all minimal projections in the center of ^, or equivalently, if and only if every point in the quasi-spectrum is a Borel set. T. Digernes and the present author [10] showed that J^ is CCR if and only if the open projections are strongly dense in the center of ?. They also showed that the complete Boolean algebra generated by the open central projections is equal to the set of all central projections in έ% whenever j^ is GCR. Recently, T. Digernes [9] obtained the converse of this result for separable C*-algebras.