Kala Namak - Black Salt
Kala namak or Bir Noon is a type of rock salt.
It is actually pink when ground and has a delicious, pungent sulphorus aroma. It is found mostly in the Himalayan mountains.
It is used through South East Asia. You will find it in Chaat masala, and chutneys.
Vegans like it , as it imparts an 'eggy' flavour. It will often be found ina tofu scramble.