Scratch Resistance of 18k/Platinum

Question

I'm considering a Rolex in 18k Gold or Platinum.  I'm wondering how scratch resistance these metals are?  I've had titanium/steel watches before and the Ti scratches up more than the Steel but both are ok for my use.  Does Au or Pl scratch up much more easily?  Is this the sort of watch I should only use on special occasions and pencil pushing? Please post here.  THanks.