White spots on the nails have usually been associated with calcium deposits or a deficiency of calcium. This is not the correct cause for these. In a majority of cases these marks are the result of injuries to the nail bed. The injuries take a long time to show up as marks on the nails and people usually forget that they had been hurt. The minor injuries could be something like the fingernail being squeezed below a heavy bag, injuries during a manicure or the alike. In a minority of cases the white marks are a result of zinc deficiency or infections.