Silk is usually made from the cocoons spun by silkworms - but there is another, much rarer, cloth known as sea silk or byssus, which comes from a clam. Chiara Vigo is thought to be the only person left who can harvest it, spin it and make it shine like gold.
How to make scrap fabric twine. This tutorial has you twisting both plies by hand, which seems tedious if you have a spinning wheel available. The only difficulty I can see is how to smoothly join in a new piece of fabric when you don't have the other ply right there to hold the join in place.