Mary Piacentino;75;of Park Manor;Monessen;died Sunday;Oct.15;1972;at 9:30 a.m.in Hollywood;Fla.;while visiting her children.  Born Oct.12;1897;in Italy;Mrs.Piacentino lived in Belle Vernon before moving to Monessen.  She was a member of St.Sebastian R.C.Church;Anita Garibaldi Lodge and the Defense Club;all of Belle Vernon.   Surviving are her husband;Jack;a son;Angelo of Hollywood;Fla.;two daughters;Mrs.Frank (Martina) Caruso of Belle Vernon;Mrs.Thomas (Tressa) Mascara of Hollywood;Fla;a brother;Andy Enrico of Jeannette;a sister;Mrs.Angela Piacentino of Jeannette;a brother and sister in Italy;eight grandchildren and four great-grandchildren.  Friends will be received from 7 to 10 p.m.Monday and from 2 5 7 to 10 p.m.Tuesday at the Shelby D.Ferguson Funeral home;Belle Vernon;where a Blessing service will be held Wednesday at 10 a.m.  Mass will follow at 10:30 a.m.in St.Sebstian R.C.Church;Belle Vernon;with Msgr. Martin J.O’Toole;pastor;officiating.  Interment in Belle Vernon Cemetery.  Shelby D.Ferguson Funeral home in charge of arrangements.