Regular shaped magnesium particles containing attrition resistant precursors and procatalysts thereof and processes for their synthesis and their use in the manufacture of polyolefins are described. A process for the synthesis of precursor particles which give highly active and improved surface area procatalysts for producing high bulk density polyolefin resins containing low fines and capable of incorporating high rubber content are described. A process for the synthesis of an attrition resistant precursors to prepare an attrition resistant Zeigler Natta procatalysts synthesized by using the precursors and to the polyolefin resin synthesized using the procatalysts is also described.