Kala namak or Bir Noon is a type of rock salt.
It is naturally 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.
This is a staple in the vegan pantry, as it imparts an 'eggy' flavour. It will often be found in a tofu scramble or in vegan mayo.
Here is a recipe fro Chaat Masala.
This recipe for chaat masala makes just under 1 cup of the masala, so multiply the ingredients if you need more.
Store your masala in a glass container, in a cool, dry place. Do not store it with other spices as the ingredients in chaat masala (especially the black salt) are highly aromatic and the other spices will take on its aroma.