The viscosity of a fluid is basically a measure of how sticky it is. Water has a fairly low viscosity; things like shampoo or syrup have higher viscosities. Viscosity also depends on temperature: engine oil, for instance, is much less viscous at high temperatures than it is in a cold engine in the middle of winter.
One small packet of 7 grams will produce about 500 grams of beads once they are hydrated. Soak overnight to a ratio of one packet of beads to 50 parts water. You can add more water or pour out any extra water when the beads expand. They can also be used to water potted/garden plants and flowers.
They are produced by a saltwater mollusk, such as the pearl oyster. The most common types of saltwater pearls used in jewelry are South Sea pearls, Akoya pearls, and Tahitian pearls. Cultured saltwater pearls show a slight difference from cultured freshwater pearls, and are thought to be closer to a perfect sphere.