Potassium is a solid, silver-white metal that is soft enough to cut with a knife and has a waxy appearance at room temperature. At temperatures above 62.35 degrees Celsius, it melts to form a silver liquid. Due to its high reactivity, potassium is stored in a mineral oil, such as kerosene.
Potassium is so reactive that it does not exist as a pure metal in nature. With exposure to air, potassium metal reacts with water vapor, forming potassium hydroxide and hydrogen gas. The heat of the reaction is sufficient to ignite the hydrogen gas, causing the metal to burn.
Potassium metal exhibits properties similar to sodium metal, but it is more expensive, resulting in limited uses for potassium in its elemental form. Potassium compounds have a wide variety of uses. They are essential to the life of plants and animals. Potassium salts occur naturally in the soil, but farmers add potash, a mixture of potassium salts, as fertilizer.
Potassium is responsible for 2.7 percent of the weight of the Earth's crust. It is the seventh most abundant element on earth. In the ocean waters, potassium is the sixth most abundant element. Mines are located on former ocean floors. Germany, Utah, New Mexico and California are the leading suppliers of potash in the world.