Black Salt known as ‘ Kala Namak’ is a pungent smelling purplish or pinkish-gray rock salt used in IndiaThe condiment is composed largely of sodium chloride with several impurities lending the salt its colour and smell. The smell is mainly due to its sulfur content. Due to the presence of Greigite (Fe3S4, Iron(II,III) sulfide)in the mineral, it forms brownish pink to dark violet translucent crystals when whole and when ground into a powder, it is light purple to pink in color
Black Salt– Names in different Indian Languages.
Hindi - Kalanamak, Bengal – Bit Noon, Gujrati – Sanchal, Punjabi – Kala Namak
Tamil - Karu Uppu, Urdu – Kala Namak
Sodium chloride provides kala namak with its salty taste, iron sulphide provides its dark violet hue, and all the sulphur compounds give kala namak its slight savory taste as well as a highly distinctive smell, with hydrogen sulphide being the most prominent contributor to the smell.
Kala Namak is used extensively in South Asian cuisines of India and Pakistan as a condiment or added to chaats, chutneys, all kinds of fruits, raitas and many other savory Indian snacks. Chaat masala, an Indian spice blend, is dependent upon black salt
Whole chunks or in powdered form Black salt must be kept in airtight containers away from heat and moisture as they release water in contact with heat and moisture.
It is quite stronger than common salt so care must be taken while using it.