There are many ways to identify natural fibres. Some of them are available only to professionals or scientists, due to the methods and/or equipment needed, but there are also simple ways to find out what fibres you are dealing with. Here are two I often use.

1. Visual inspection: colour, aspect of the fibre (shiny, matte, etc.)
   

2. The burning test: set light to the end of the rope (or cut out a short segment if you want to be extra careful), just long enough to burn the fibres so you can evaluate the burnt smell.
   

3. ✦Burnt jute smells like burnt paper or hay
   

4. ✦Burnt hemp has a more pungent, acrid smell
   

5. ✦Burnt flax is close to hemp, but slightly different.
   

6. The trick is to educate your nose to differentiate hemp from flax, so it’s better to try with at least one sample you are sure of. Even after being washed or dyed, natural fibres will always produce the same smell when burnt.
   

Warning: jute fibres are highly flammable, so make sure you control the situation 100%...