Dry precipitated calcium carbonate and a slurry of precipitated calcium carbonate (“PCC”) particles at least partially in the form elongated entities, especially of nanofibers or nanochain like agglomerates constituted by at least two interconnected primary particles, and preferably, with a content of scalenohedron particles, is provided having opacifying properties. The slurry may be produced on site of its use and, due to its high concentration of CaCO3, may be applied directly after its manufacture.