The Valley of Death, the hottest place on the planet, is considered the birthplace of this stone. The air temperature there reaches 57 degrees Celsius.
It was in the intermountain trough in the Mojave Desert in the western United States, in California, that Colemanite was found for the first time. It happened almost thirty years after the end of the California gold rush, during which thousands of people rushed west in search of the precious metal.
By 1884 the deposits of readily available gold had all but been exhausted. But at one of the mines in Death Valley, owned by William Tell Coleman, a new mineral, colemanite, was discovered. Initially, the owner of the mines suggested that it be called by another name, smithsonite, but that name never stuck. It turned out that the stone contained the chemical element boron, in a quantity suitable for industrial mining. Boric acid derived from colemanite was widely used in medicine as an antiseptic. French chemist Jean Baptiste Dumas discovered that its solution did not irritate wounds, did not stain linen, had no bad odor or taste. Therefore, many of the "home remedies" known at the time, such as hydrogen peroxide, manganese and carbolic acid, were increasingly replaced by boric acid.
Thousands again went to the California mines, only now obsessed with boron fever. At first, the extraction of Colemanite really brought in enormous profits. But because the mineral was not extracted in its pure form, the waste rock had to be removed. The material had to be heated to high temperatures of over 750 degrees at very low pressure for short intervals of time. All this implied additional costs, and soon the owner of the deposit went bankrupt, and a few years later the mining towns in the area were irretrievably deserted.
The situation was not saved even by the fact that up to 1926 colemanite was the main source of boron. And although in the middle of the 20th century, its main competitor - the mineral kernite - was discovered, colemanite still retains its leading position, being the most commercially consumed boron mineral by the industry.
Taking into consideration the high efficiency of colemanite, many attempts were made to create a synthetic version of the stone. It turned out that this mineral, which is the result of chemical reactions, is unstable and has inferior properties to its natural counterpart.
One more reason to create an analogue of this stone is the rarity of its deposits, especially the ones that are profitable to develop. The largest of them are located in the Valley of Death in California, in Chile's Atacama Desert and in the Salinas Grandes Salt Marsh in Argentina. The largest proven reserves of colemanite are concentrated in Turkey and amount to more than 25 billion tons.
The practical use of the mineral and the compounds derived from it is extremely diverse. Most of it is consumed by the glass and ceramic industries to make optical glasses, refractory products and porcelain. Other raw materials are used in the soap industry and in the production of bleaching agents. Boron is also used in medicine as an antiseptic, in metallurgy and in the perfume industry. In addition, it serves as a microfertilizer for plants.
The mineral has also attracted the attention of scientists because of its unusual ability to accumulate an electrical charge when the temperature changes. This property, known as pyroelectricity, is related to the structure of the mineral's lattice and theoretically cannot be shown in minerals such as Colemanite. But the mineral is an exception to the rule, and science has never provided an explanation for this fact.
Translated by Diego Monterrey, for Northwest Forpost.