Or, Harris Tweed, if you want to be more “high brow”.
Project notes and more photos are on my Rav project page.
The yarn is Sweet Georgia Superwash Worsted in “dutch” which is a warm, tonal orange. I love it. Good idea in theory, but the waffle/tweed texture is not slouchy enough for a true slouch hat. I’ll still wear it, though, but in future I think I’ll stick to stocking stitch for slouching.