Order from a scam artist online and you may find yourself with a box filled with rocks instead of what you had ordered. The suspicious spice shopper looking for kala namak could think they had been swindled at first glance.
This moderately obscure Indian ingredient adds a sulfurous kick typically used for legumes like chickpeas, but can be used anywhere a hint of egg-yolk like flavor is desired (not surprisingly, it’s caught on among some vegans).
My favorite use is to add a bit to cream cheese on a bagel for a twist on the breakfast sandwich. It’s salt, so don’t use a heavy hand. If you buy it in large rocks, you need a good spice grinder to turn it into powder.