Silk is a protein fibre spun by silkworms as they make their cocoons. Silk production was developed in ancient China thousands of years ago.

Silk is generally considered sustainable because it is a natural fibre from a renewable resource and is biodegradable.

However, it can have a negative impact on the environment when pesticides and fertilisers are used to grow the mulberry tree needed to feed the silkworms. A significant amount of water and energy is also required to transform the cocoon into a usable yarn. 

Silk is produced by the silkworm, so it is not a vegan option. To produce conventional silk, the silkworms are boiled and killed in the process, which is considered animal cruelty. A process called Peace silk or Amhisa silk involves allowing the moth to leave the cocoon before boiling it, but as the silkworms have been reared for thousands of years for this purpose, they cannot survive long when released into the wild.

Silk belongs to SANE Approved Material List. Additional environmental requirements for silk production are currently being evaluated and might be added to the next version of SANE standard . 
It means that a product made of at least 90% silk (or blended with other SANE Approved Material) and produced in a facility holding a SANE Scope Certificate is eligible to be certified SANE.

Copy partner: Sustain Your Style; Picture: Quang Nguyen Vinh
Other sources: CfDA; MF. Astudillo, G. Thalwitz, F. Vollrath. Life cycle assessment of Indian silk;