Everyone knows yarns can be made of wool, cotton and acrylic. People often just call yarn “wool” but there are many other fibres that can be made into yarn, some of which are unexpected. There are some unique yarns out there that are made from unusual fibres.
Some we don’t even think of being “fibrous”. One example is milk. Milk is a liquid. Who would think it could be made into yarn? Someone thought of it and figured out a way to spin the milk protein into fibres and make a yarn out of it. Milk is cooked into a slurry with the milk proteins solidifying out, which are then pushed through the tiny holes of a spinnarette and formed into filaments which are spun into a yarn. Milk yarns have a nice sheen to them but do tend to be a bit on the pricey side.
Another unusual fibre made into yarn is paper. We just got in some yarn from King Cole (http://www.kingcole.com/knitting-wool/raffia/) and Rico (http://www.rico-design.de/en/hand-knitting/hand-knitting-overview/creative-paper.html) that are made from 100% paper fibre. What I find most amazing about it is that it is hand washable. Now this is not a yarn you are going to want to wear on next to your skin but it has a lot of structure so it is great for making hats or baskets or placemats. Usually this yarn is crocheted as most items need that extra bit of stiffness you get from crocheting but it can also be knit. Because the yarn is stiffer than most it makes for great sun hats as the brim stays stiff.
There is a new yarn out from Bernat called Maker that is a cotton acrylic blend but it looks like t shirt material. There are instructions on line as to how to take old tshirts and make them into yarn but Bernat has done it for you and it is all ready to knit or crochet.
You can knit or crochet with wire as long the wire is flexible. There are some beautiful crocheted and knit wire jewelry that can be found for sale online.
Let your imagination run wild and try knitting with some of these unique yarns.