These pure cow ghee diyas are also called panchagavya vilakku in the southern part of India traditionally used for special occasions like Dewali and Tulsi Pooja. A diya diyo deya divaa deepa deepam or deepak is an oil lamp usually made from clay with a cotton wick dipped in ghee or vegetable oils. Diyas are native to the Indian subcontinent often used in religious festivals such as Navratri Dussehra Diwali Etc.