Shungite has a long history of being used for water purification. I find that leaving two to four of these small pieces in your water bottle for a few hours really changes the water. I prefer multiple small pieces over one large piece because most water bottles have small mouths. Some people also like to keep one in their pets water bowl.
Other uses for shungite: detoxing from emf’s (electrical energies radiating from cell phones, computers, etc), cleansing energy field from harmful or unwanted energies, it is grounding spiritually.