RRB RPF RPSF SI and CONS Model Papers 5 with solutions

(3) The colour of pure diamond is light blue. The colour of the Diamond is determined by the amount of impurities or structural defects that cause the coloration. The scale and grading for white or colourless diamonds goes from 'D' (colourless) to 'Z' (dark yellow). The Blue color in Diamonds occur due to the presence of the element Boron (B) which changes the conductivity of the diamonds.