Bamboo is a terrific semi-ecofriendly yarn with the softest of hands.  It is smooth and dreamy. The bamboo fibers are so smooth that this yarn is wonderful to work with even when your hands are super dry.  Mix with cotton or Tencel to create a strong but drapey fabric.

(I say semi-ecofriendly because while bamboo can be processed without chemicals, it's extremely expensive to do so. Most commercially available bamboo is processed like rayon.  However, the crop of bamboo is among the most "green" to produce - it needs no fertilizers or pesticides and a grove of bamboo will regenerate every 4-5 years.)