Can I reuse the stones, and if so, for how long? — Shungite Stone for Water Purification, Fraction 10–20 mm

Yes, you can reuse the stones. Their porous structure and large active surface area are meant for repeated contact with water. There is no fixed expiration date; their effective lifespan depends on usage frequency and water quality. With regular use (e.g., daily), a batch may last several months to a year before you might notice a change in their appearance or a reduction in their effect on water taste. To maintain them, rinse the stones under running water every few weeks to remove any accumulated film. Occasionally, you can leave them to air-dry completely. Over a very long period, the stones may become smoother or slightly lighter in color, which is normal wear. Ultimately, they are a natural mineral product and will slowly wear down. When they have significantly diminished in size or you no longer find them effective for your purpose, it's time to replace them. Store unused stones in a dry place.