Sendha namak, also known as saindhava lavana or simply rock salt, is a type of salt that is commonly used in India and some other Asian countries. It is a natural, unprocessed salt that is harvested from salt mines, primarily in the Himalayan region. Sendha namak is often used as a culinary ingredient, especially during religious fasting (vrat) periods in Hinduism when regular table salt (common salt) is avoided.