Fair Isle knitting (a type of stranded colorwork) is typically done in two ply fingering weight Shetland wool yarn. I've got fingering weight, but most sock yarn usually isn't two ply (three ply is more durabe), and even the sock yarn that is two ply (Madelinetosh Tosh Sock) isn't Shetland wool. Shetland wool is "hairier" and sticks to itself better than superwash Merino. This is important for things like steeks. (Again for the non knitters - steeks are when you cut your knitting open. Stranded knitting is easier to do in the round than back and forth. This means things like armholes and necklines in a pattern like this are typically knit with steeks - little bits of extra knitting that will be cut open later.) I've never tried steeks before. I've seen them, I've heard about them, but I've never done them.
And this concludes today's knitting trivia lesson. Didn't mean to post a knitting trivia lesson, but that's what happened when I sat down this morning.