| Potassium makes up about 1.5% of the weight of the Earth's crust and is the seventh most abundant element in it. As it is
very electropositive, potassium metal is difficult to obtain from its minerals. It is never found free in nature. Potassium
salts such as carnallite, langbeinite, polyhalite, and sylvite are found in ancient lake and sea beds. These minerals form
extensive deposits in these environments, making extracting potassium and its salts more economical. The principal source
of potassium, potash, is mined in Saskatchewan, California, Germany, New Mexico, Utah, and in other places around the world. 3000 feet below the surface of Saskatchewan are large deposits of
potash which are important sources of this element and its salts, with several large mines in operation since the 1960s. Saskatchewan
pioneered the use of freezing of wet sands (the Blairmore formation) in order to drive mine shafts through them. The oceans
are another source of potassium, but the quantity present in a given volume of seawater is relatively low compared with sodium.
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Occurrence