This is not a small 10 gram little package-it is 8 ounces = 225 grams- will make up to 6 gallons or 24 quarts of Pearls depending on water used. The "purer" the water, the larger the crystals will grow. Distilled water is the best.
Material: non-toxic super absorbent cross-linked polymer. How long does it last: It is reusable and can last for up to 4 months as long as you keep adding water.