Chlorophyllin is a beautiful green powder extract derived from the extraction of chlorophyll from the leaves of plants.   It is a well known natural dye used in foods, cosmetics, and in fabric dyeing processes amongst many other applications.  It is a very strong dye so you don't need very much - 5g is sufficient to dye 200g hanks of wool to a dark to medium green colour.  Obviously you should always experiment to get your desired shade before adding expensive wool yarn or fabrics.  It can also be used to colour soaps a rich green.
 
Shades obtained can vary from olive green through to dark to pale bluey/sea green green colours, and is very stable and colourfast.  It can be used to pre-dye or even over-dye to get combinations of colour.
 
Chlorophyllin provides a rich colour.  To use in fabric or wool dyeing, mix a paste with 5g  and a small amount of warm water, and add the paste to your dye pot.  Add the wetted, mordanted fibre and gently simmer for 45-60 minutes stirring occasionally.  Leave to cool, and wash.
 
Pack size supplied is 25g