Puranic Encyclopaedia: A Comprehensive Dictionary with Special Reference to the Epic and Puranic Literature c5.10

c5.10

4) The weapon (Vajra) of Indra was made from a bone. A story occurs in the Mahābhārata, which says that the Diamond-weapon of Indra was made of a bone of Dadhīci. The asuras went to fight with Indra under the leadership of Vṛtrāsura. Indra tried his utmost to kill Vṛtrāsura, but he could not. At last Indra approached Brahmā, who told Indra that if a bone of the hermit, called Dadhīca was obtained it could effectively be used against Vṛtra. Accordingly Indra went with Nara and Nārāyaṇa to the banks of the river Sarasvatī and entered the hermitage and bowed before the shining hermit Dadhīca and informed him of their errand. The hermit replied that he had no objection in giving his bone to save the gods. Saying thus the hermit discarded his life. Indra took the bone of Dadhīca and made his weapon of Diamond (Vajra) with which he killed Vṛtra and his followers. (Mahābhārata, Chapter 100).