The quality and characteristics of wool, mohair and alpaca yarn can be changed and enhanced by using natural fibres like bamboo, linen and hemp. Silk is another option. It is made by moths and presents no production problems. The cocoon is either unwound by hand, which is expensive, or cut open so that the filament is in smaller lengths.

We use tussah silk to blend with natural fibre which means that the silkworms are not killed. Tussah silk is wildcrafted which means that the worms live naturally in tropical or semi tropical forests and are therefore both organic and suitable for vegetarians. Although there are many different varieties, Tussah silk is rich in tannin and ranges from beige to brown in colour.

The Wikipedia has a useful summary regarding silk and additional information is available from the Vegan Society.

There are some environmental disadvantages to the use of vegetable fibre in that production demands more water and the addition of chemicals to soften the material. Cotton is problematic in that the fibre is short and will not pass through traditional wool spinning machinery. 

Our machinery can handle the other materials mentioned, but these need to be sufficiently soft to avoid damaging the wire on the carding sets that straighten the fibre. 

We have produced some excellent results using natural fibres like, bamboo, linen and hemp. For example we've used bamboo hemp and flax to blend with natural fibre to produce a lighter weight yarn. Being white, bamboo lightens the finished colour.

Currently we are experimenting with flax and hemp and have made some yarns for Blacker Designs with flax and Blue-faced Leicester wool.