This sacred river stone is found only in one place on earth, the Narmada River, an inlet of the Ganges. When held they bring an overall sense of calmness and well-being. The dark yoni markings are feminine, and the shape is masculine; symbolizing a perfect balance. Each stone is unique. The structure of Shiva Lingam is comprised of Crypto Crystalline Quartz. These measure approximately 3 to 4 inches long by 1 to 1/2 inches wide.