Cotton and Nylon, who knew there was a difference?

I would prefer to wear cotton, personally...however, when creating, I like the effect of nylon over cotton. The olive and aqua color flowers are made from nylon thread, which leaves a neat-looking sheen to the finished product...the purple and peach are made from cotton thread, which is still fun, just not as crisp looking....yes, this is a very rough looking picture, but I hope it helps in telling the difference between the two.