Kala namak (Hindi for "black salt") is a kiln-fired rock salt used across South Asia, prized for a pungent, sulphurous, distinctly egg-like aroma. Pink-grey to dark violet in lump form and pinkish when ground, it is a staple seasoning in Indian chaats, raitas and chutneys — and a near-magical tool for giving vegan dishes an "eggy" flavour.