Fun fact, it actually does come up in the dialogue of part 1 when Paul and Jessica are running for the rocks from the sand worm, just before they meet the Fremen. It's under some of the music/ambience but Paul steps onto some and there is an audible thump before he notes that it's drum sand, so it is very briefly brought up.

You can see the scene here:

https://youtu.be/6hU78elkK6Q?t=84