The fibres that are used in the fabrication of a composite can be divided into two broad categories as follows:
A. Natural fibres and
B. Advanced fibres
A. Natural fibres
The natural fibres are divided into following three sub categories.
o Animal fibers: silk, wool, spider silk, sinew, camel hair, etc.
o Plant/vegetable fibers: cotton (seed), jute (stem), hemp (stem), sisal (leaf), ramie, bamboo, maze, sugarcane, banana, kapok, coir, abaca, kenaf, flax, raffia palm, etc.
o Mineral fibers: asbestos, basalt, mineral wool, glass wool.
B. Natural fibresAdvanced fibers:
An advanced fibre is defined as a fibre which has a high specific stiffness (that is, ratio of Young’s modulus to the density of the material, 
) and a high specific strength (that is the ratio of ultimate strength to the density of the material, 
).
What are the advanced fibres?
The fibres made from following materials are the advanced fibres.
1. Carbon and/or Graphite
2. Glass fibers
3. Alumina
4. Aramid
5. Silicon carbide
6. Sapphire
