Cut rind into 1/3-inch strips. Cover in cold water and bring to a quick boil. Reduce heat, and let simmer slowly until transparent, about 30 minutes.
Drain, and reserve 1 1/2 cups of liquid.
In a heavy pot, completely dissolve sugar in reserved liquid. Add honey and lemon peel, and bring to a boil, skimming as needed. Add drained rind and seeds and boil gently over medium heat, for 15 minutes. Remove from heat, cover, and set aside overnight.
Boil again over medium heat, until syrup thickens, about 15 minutes. Test for doneness.
Add lemon juice and mastic or cardamom 5 minutes before jam is done. Let jam cool completely then store in a sterilized jar.