Kala Namak; (Tamil) "இந்துப்பு" , also known as black salt or kala loon or black Indian salt, is a salty and pungent smelling condiment

Condiment

A condiment is an edible substance, such as sauce or seasoning, added to food to impart a particular flavor, enhance its flavor, or in some cultures, to complement the dish. Many condiments are available packaged in single-serving sachets , like mustard or ketchup, particularly when supplied with...

 used in South Asia

South Asia

South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...

. The condiment is composed largely of sodium chloride

Sodium chloride

Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...

 with several impurities lending the salt its colour and smell. The smell is mainly due to sulfur content. Due to impurities in the mineral, it is brownish pink to dark violet translucent stone when whole and when ground into a powder, it is light purple to pink in color.

Kala namak is a type of natural volcanic halite

Halite

Halite , commonly known as rock salt, is the mineral form of sodium chloride . Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities...

.