Indian Black salt (also known as Kala Namak), is a crushed Indian volcanic rock salt which isn't actually black but more reddish grey. This blockbuster may smell a little odd (this is because of the sulphur compounds) but don't let this deter you - it dissipates very quickly once in food and what it lacks in smell it certainly makes up for in taste. This salt's taste is savoury and just like hard boiled egg yolks, so it is perfect if you want a flavour of egg in a vegan dish.