Kala Namak, or Indian Black Salt (also called Nirav Black Salt or Sanchal), is a special unrefined mineral salt from Darjeeling, India. It is a volcanic rock salt mined in central India. The ground salt is not black, but more of a coral pink or pinkish gray, and has a strong, sulfuric flavor. These colors come from the presence of trace minerals such as magnesium, as well as volcanic iron.
Kala Namak is used in Indian cuisine as a condiment, most commonly with snack foods. It is used in chaats (fruit glazes), chutneys, raitas (yogurt and cucumbers mixes), fruit salads, and savory deep-fried snacks. The finishing salt has a strong sulfur taste and smell. While this unique quality is often diffused when cooked, it nonetheless adds a special taste of eggs.