A Visual Encyclopedia of the Periodic Table

The salt forms part of rocks deep underground before

it is dissolved by the stream and flows into the pools.

Evaporation can also be used to collect salt from seawater

or other salty water sources (known as brines). Today,

however, most of the world’s salt comes from underground

mines containing thick layers of salt that are a result of

ancient seas drying out. Over millions of years, that

dry salt has become buried under dense layers of rocks.

This so-called “rock salt” is sometimes unearthed using

excavators. At other mines, it is washed out by piping in

warm water, which dissolves the salt. The brine is then

pumped up to the surface for evaporation.

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