If your wanting a natural purple for your easter eggs I suggest using beets or cabbage.
HOWEVER, there is a catch to getting the purple color and getting it to stay purple and not turn grey.
Beets or Purple Cabbage chopped fine
Place in a stainless steel sauce pan
Cover twice as deep with Vinegar and add one cup of sugar to the mix.
Bring to a boil.
Strain the vegetation out of the liquer.
Return the dye juice to the sauce pan.
Bring back to a boil and then remove heat source.
Place your eggs in the hot liquid and roll around in the liquid.
Do this for about 15 minutes.