Is it said that carrying crystals on your body or wearing them as jewellery allows positive energy of crystals to be transferred to the body’s energetic field, also known as the bodies seven chakra's. Therefore, when crystals are put with water the water absorbs the energetic vibrations of the crystals, stores the energy, and when you drink the water you are essentially ingesting that energy.
Don’t be limited with just the crystals that come with the bottle. You can unscrew the bottom and change out crystals however you’d like. Use any gemstones as the stones do not touch the water, so it’s clean and safe.