I recently started my first knitting project. I decided to stay very simple and quick: a baby's scarf in plain garter stitch. I used 8 ply alpaca wool in lovely natural colors which was my MIL's before she passed last year. I used size 4 1/2 needles, plastic if it matters. Everything is going pretty well except for the fact that one of the strands which makes up the yarn has snapped. I can send a photo if I'm not describing this well or anyone needs to look to see. This happened the first time with the same ball of wool while I was casting on but I assumed it was a fluke... now I'm not so sure.
Could someone please suggest the cause? And how I should fix this? I'm hoping it's not something with the wool, like because it's older it's not good anymore as it's lovely and would be a sentimental thing to use my MIL's wool on her grandchild's baby stuff. It appears to be fine to my eye, nothing obvious. It's fairly fine diameter, not real chunky (22sts/10cm) so I have to imagine trying to somehow twist it back together would be a delicate opperation. I'd really hate to unwravel everything and start again if I don't have to.