The sanskritist N. Kazanas has argued that the term could denote a supernatural, occult or magical protective force or field. In the Rig Veda, there are also purs made of metal (purās ayasīs in 10.101.8). In Aitareya Brahmana, there is copper/bronze, silver, and golden pur. The Rig Veda mentions also a mobile Pur.