Alum 
Basic unit 250g
 
Alum is the common name for Aluminium Potassium Sulphate. It is the mordant to use for protein fibres such as silk or wool. It is a simple non toxic compund refined from bauxite and ours is a food grade quality that is free from iron or other impurities.
 
Alum can be used at 10-20% on the weight of the fibre.
 
100g will mordant 500g fibre when used at 20%.