For those unacquainted with the story of King Midas, he was the one who wished everything he touched would turn to gold, but found how terrible this was (he couldn't eat/drink anything of his own power). I have dubbed this the 'Midas Effect', as I think it's a fitting name.
Another example of this in sci-fi is in the Lost in Space episode All that Glitters (see link for a description of what occurs if you're unfamiliar).
Now, onto the question - what is the minimum size of this effect? If this actually happened to everything a person suffering this effect touched (ie atoms), they would be surrounded by gold/platinum all around them (meaning breathing would not be possible), so there must be a minimum size, but what would this be? (I am assuming that there is a general principle, so I'm looking for the smallest item touched by Midas that turned to gold [I am even willing to accept the smallest item Dr Smith touched also, if that is smaller still])