For this purpose accurately take out on one thread up and down fabrics. These  threads are accurately fire by a match.   
If  the thread burns quickly, in regular intervals, with a bright flame and smells,  as if the paper burns, and ashes, which fall from a light touch - it means that  a fabric from a vegetative fiber (cotton,  flax) or from viscose. 
Acetate silk also burns quickly. On the thread end there  are ashes in the form of a hard black-brown small knot. At burning exhales a  smell of acetic acid. 
Kapron and nylon do not burn, and form a soft small  knot. 
Wool and natural silk burn badly. On the thread end is formed the black small knot ashes, which fall from a light touch. At burning exhale a smell of a burnt bone.
