Bring 1 cup water and sugar to a boil over medium high heat and simmer just long enough until they combine to form a syrup, about 3 minutes.
In a bowl, combine syrup, rosa liquid, lime juice and mint and stir well. Pour mixture into a shallow dish, like a casserole dish, and place in the freezer.
After an hour, begin to scrape at the forming ice in the dish. Break apart any big chunks.
Close freezer but repeat every 30 to 45 minutes for another three hours, or until granita is flakey and there is little to no liquid left. Serve.