Help creating an acoustic foam material

Hi, I've seen some acoustic foam assets available but I'm totally feeling them. Specifically I'm wanting to add the glitter effect (you can see it in the acoustic foam here) into the material and I can't really make it out from the assets. Ideally I'd like to build the material from scratch anyway. Any tips for adding a subtle glitter effect in? Here's a pic of what I'm after. Thank you.