Jul 1, 2014 - IS 8570:1977. Press paper for electrical purposes. 42. Oct 2011. IS 9043:1979. | ISO 444(1965). Method for grading (by size) of phlogopite mica blocks, thins and splittings. 43. Oct 2011. IS 9044:1979. | ISO 5972(1978). Method of measur