The metal ranks seventh in abundancy. They have formed rather large deposits from which potassium and its salts can readily be obtained. Potash is mined in Germany, New Mexico, California and Utah. Presently, only small amounts of potassium can be found in the ocean.
Potassium is a constituent of all plant and animal tissue and a vital component of fertile soil.
The largest demand for potash has been in its use for fertilizers. Potassium is an essential constituent for plant growth and is found in most soils. Potassium bromide is used in photography, engraving and lithography, and in medicine as a sedative. Potassium chromate and potassium bichromate or potassium dichromate are powerful oxidizing agents used in matches and fireworks, in textile dyeing and in leather taning. Potassium iodide is used in medicine in the treatment of rheumatism and overactivity of the thyroid gland.