Noro yarns are known for their vivid hues and unique combinations of colors found in the natural world (think of the red leaves of maples or the cerulean blue of the sky). These colors also tap into the multiplicity of shades found around us. Leaves may appear one shade of green from afar, says Mr. Noro, "but in reality they come in countless variations of green. By mixing colors, we can give a more natural feel reminiscent of oceans, mountains, flowers, trees and so on." Noro's insistence on maintaining the integrity of the dyeing process—taking sufficient time to apply color is crucial—creates these rich, complex hues while reducing ecological impact.

Silk is a natural protein fiber, produced by certain insect larvae when forming coccoons. The best known silk is obtained from the larvae of the mulberry silkworm. To produce 1 kg of silk, 104 kg of mulberry leaves must be eaten by 3000 silkworms. As a fibre, silk is smooth and soft, and it is one of the strongest natural fibres. It has excellent drape, but no elasticity the way that wool does.

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.

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.