Merino sheep create a wool with a long, smooth fibre that is lightweight, warm, and soft. Like all wool, it has excellent breathability and does an excellent job regulating temperature in garments. It is a very popular type of wool to use for hand knitting yarn, and is a great choice for socks and garments worn close to the skin.

Cotton is a plant fibre made from the cotton plant (surprise!). It is absorbent, soft, very easy to care for and a popular choice for garments and household items like washcloths and towels. As a plant fibre, however, it will not retain warmth very well, so is less ideal for warmer winter items.

Alpaca fiber is a natural, soft, and warm fiber that comes from the hair of alpacas. It's used to make a variety of clothing items, including sweaters, socks, and scarves. It is warmer than wool, and comes in 22 natural colours. It has excellent drape, and takes dye very well.

Mulesing is a controversial farming practice used, predominantly in Australia, to prevent the parasidic infection flystrike. While mulesing prevents infection, it is a very painful procedure for the animal to endure, and more humane alternatives exist. This practice is banned in many areas of the world. If a yarn is marked as mulesing free, that means that no animals were treated this way during the production of the yarn.

Nylon is a synthetic material that is often used to provide structure, stability and strength to yarns made with other, softer fibres. A nylon content of at least 15% is recommended for socks.