Long before the Himalayan mountains existed — roughly 250 million years ago, during the late Permian and early Triassic periods — a vast, shallow sea covered what is now the Punjab region of Pakistan. As tectonic plates slowly collided and the Indian subcontinent crashed into the Eurasian plate, that ancient ocean was sealed beneath layers of rock, lava, and sediment. Over geological epochs, the seawater evaporated under immense pressure and heat, leaving behind crystallized salt deposits of extraordinary purity.
The Khewra Salt Mine, located at the foothills of the Salt Range mountains in Punjab, Pakistan, is the world’s second-largest salt mine and the source of virtually all authentic Himalayan pink salt. The mine stretches over 110 square kilometers at depths ranging from 250 to 900 meters below the surface. Its labyrinthine tunnels — some large enough to drive trucks through — have been carved out over centuries, creating an underground cathedral of pink, rose, and crimson salt walls.
Legend has it that the deposits were discovered by Alexander the Great’s army in 326 BCE, when his horses began licking the salty rocks during their march through the region. However, the first recorded mining operations date to the Mughal era in the 1200s. The British colonial government industrialized the mine in the 1870s, designing the tunnel system still in use today using a “room and pillar” method that leaves 50% of the salt in place as structural support.
Today, the mine produces approximately 350,000 tons of salt annually, though only a fraction of this meets the quality standards for culinary-grade pink salt. The mine is also a major tourist attraction, featuring an underground mosque, a post office, and even a small clinic — all carved entirely from salt.
The Science of the Pink
The pink color of Himalayan salt comes primarily from iron oxide (rust) trapped within the crystal lattice during formation. The concentration of iron oxide determines the intensity of color: trace amounts produce white or pale pink crystals, while higher concentrations create deep rose, red, or even orange hues. Other trace minerals — including magnesium, potassium, and calcium — contribute to subtle variations in color and flavor. Spectral analysis has identified 84 distinct trace elements, though sodium chloride still makes up approximately 98% of the salt’s composition.
Unlike sea salts harvested from modern oceans, Himalayan pink salt is considered remarkably free of modern pollutants — microplastics, heavy metals from industrial runoff, and other contaminants that increasingly affect ocean-harvested salts. The salt was sealed underground long before industrial civilization existed, making it one of the purest mineral salts available. This geological purity is one of its most compelling selling points, especially for health-conscious cooks.
The mining process itself is notable for its environmental consideration. Rather than blasting — which would shatter the delicate crystal structures — miners use a combination of careful drilling, cutting, and hand extraction to remove large blocks of salt that are then processed into various grades. The highest-quality crystals, those with the most vibrant color and fewest impurities, are reserved for culinary use. Lower grades are used for bath salts, salt lamps, and industrial applications.
