I’m a sucker for anything that’s "millennial pink," that pastel, dusty shade of pink that’s taken over Instagram, and, if I’m being completely honest, the gorgeous rosy hue is why I even bothered to take note of Himalayan salt in the first place. But once I noticed Himalayan salt, I couldn't avoid it. Himalayan salt has been popping up everywhere: in bottles on grocery shelves, as a plank for grilling or baking, even as a glowing, crystal lamp that's supposed to purify your air and your energy or something. So what is Himalayan salt, why is it so popular all of a sudden, and—most relevant to my interest—why is Himalayan salt pink

Well, as the name suggests, Himalayan salt comes from salt mines in the Himalayas. Yes, those Himalayas. But Himalayan salt doesn't come from Mount Everest. Most of the pink salt you see on grocery store shelves and for sale online comes from salt mines in Pakistan. And most of that Pakistani salt comes from the Khewra salt mine in Punjab, in the eastern half of the country, north of India.

According to Atlas Obscura, the Khewra salt mine is the world's second largest salt mine, producing 325,000 tons of salt per year—though that number differs depending on your source. According to Express Tribune, a Pakistani newspaper, these salt mines produce "over 850,000 tons of rock salt annually." Really, any way you look at it, it's a lot of rock salt.

The Khewra salt mines are so large that they have their own internal infrastructure for the thousands of workers who mine the salt by hand. There's a mosque, a post office, even "small salt versions of the Great Wall of China, the Mall road of Murree, Lahore’s Shimla hill, and the Minar-e-Pakistan in Lahore," write the folks at Atlas Obscura—all made out of salt bricks, of course.

All of this is cool, but it still doesn't explain why Himalayan salt is pink. Himalayan salt is pink because of the minerals within these underground sea salt deposits. These deposits formed thousands of years ago when, "An ancient inland sea slowly evaporated, leaving behind expansive mineral salt deposits," explains SaltWorks, which sells Himalayan salt sourced from Khewra. "As tectonic activity shifted the earth, the seabed was hermetically sealed, buried under intense pressure. As the continents continued to shift, the rock surrounding the seabed was forced upward, forming the mountain ranges where the mines are now located." 

The salt is just like any other sea salt in terms of basic composition. The color, then, is due to trace minerals. As Shanna Freeman writes for How Stuff Works, pink Himalayan salt "gets it color from calcium, magnesium, potassium, copper and iron." But Himalayan salt isn’t the only type of pink salt that’s out there. There’s alaea salt, also known as Hawaiian salt. Freeman explains that this salt is reddish-pink because of the "iron oxide added in the form of volcanic clay."

Those trace minerals are why Himalayan salt has a slightly different taste than regular kosher salt or even sea salt; it tends to be described as more subtle, better as a finishing salt than something to add to a regular recipe. And since Himalayan salt is generally more expensive than regular table salt, it's not really an ingredient you want to use in huge quantities. Besides, it looks so pretty that you'll probably want to show it off.