The phallus symbol representing Shiva is called the lingam. It is usually made of granite, soapstone, quartz, marble or metal, and has a yoni or vagina as its base representing the union of the male and female sexual organs. Devotees circumambulate the lingam and worship it throughout the night. It is bathed every three hours with the five sacred offerings of a cow, called the panchagavya - milk, sour milk, urine, butter and dung. Then the five foods of immortality - milk, clarified butter, curd, honey and sugar are placed before the lingam. Dhatura and jati, though poisonous fruits, are believed to be sacred to Shiva and thus offered to him.