Another very popular but often misunderstood icon is the symbol of Lord Shiva which is called Shivalinga. Some Hindu sects believe that Lord Shiva fulfils two roles - he is the benefactor and destroyer. The energy (Shakti) with which he performs these functions is like fire (fire can destroy but it is also essential for sustaining life). This omnipotent power of God which creates, preserves and destroys is represented by a flame of fire. In the vedic period, the sacred flame was kindled in havan kund. Later, in the Puranic period, the symbolic flame was represented by Shivalinga.
The base of Shivalinga is called Brahmabhaga - representing the creator Brahama, the Octagonal middle part is called Vishnubhaga representing the preserver Vishnu and the projecting flame like cylindrical part is called Rudrabhaga. Shivaling is usually made of black stone. The pouring of milk on the shivalinga is meant to be the same as pouring of ghee on the sacred flames of a havan yagna. Both these acts represent selfless action.