Kala namak (Urdu / Hindi) or bire noon (Nepalese; literally "black salt") is a type of rock salt, a salty and pungent-smelling condiment used in South Asia. It is also known as "Himalayan black salt", Sulemani namak, bit lobon, kala noon, or pada loon. It is found mostly in the Himalayas. The condiment is composed largely of sodium chloride with several other components lending the salt its colour and smell. The smell is mainly due to its sulfur content. Because of the presence of Greigite (Fe3S4, Iron(II,III) sulfide) in the mineral, it forms brownish pink to dark violet translucent crystals when whole. When ground into a powder, its color ranges from purple to pink. Kala namak has been praised in Ayurveda and used for its perceived medical qualities.