Mix pectin and sugar in a small bowl and set aside.
In a heavy bottomed saucepan, bring blueberries, lemon juice, lavender and calcium water to a gentle simmer. Continue simmer and stirring very frequently for 10 minutes to infuse lavender into jam.
Add pectin/sugar mixture and continue to boil for 2-3 minutes, until completely dissolved. Remove from heat. Remove lavender bundle or sachet.
Ladle into sterilized half pint jars, leaving 1/2" headspace. Wipe rims of jars and screw on lids and rings, finger tight. Process in a water bath canner at a full boil for 10 minutes.
After processing, remove jars from canner and allow to cool for 24 hours. Check for seal and store in a cool dark place. Will keep for up to a year in pantry, refrigerate after opening.