Natural coral sand collected from the beautiful seabed of subtropical Okinawa is composed of reef-building corals that form coral reefs and foraminifera that are familiar with star sand. These organisms ingest minerals such as calcium and magnesium from seawater to form skeletons and shells. Coral sand, which is a skeletal fossil of this reef-building coral, has many kinds of essential minerals such as calcium and magnesium (about 20 kinds of essential minerals) that are absolutely necessary for humans to live in good health from their daily diet. Is contained in a large amount. When such coral sand is used as a water purification material, minerals are eluted into the water, making it possible to create delicious mineral water with a natural balance. At the same time, coral sand shifts acidic drinking water to weak alkalinity, removes the odor of karuki in tap water, and has innumerable fine pores of 10 microns or less, so heavy metals, foreign substances, etc. Adsorption removal can be performed.