The study revealed several remarkable findings. Most notably, I observed that confinement generally makes the solid salt crystals more stable and significantly increases their melting points ...

“Refined free-flow salt and crystal salt for domestic and industrial use are being supplied from Gujarat. The price is also viable for traders to repack and sell them to other areas,” he sai ...

There's a lot of pressure, the weight of the overlying rock bearing down, so that combination of high temperature and high pressure is what's necessary to grow diamond crystals in the Earth.