Nitratine or nitratite, also known as cubic niter (UK: nitre), soda niter or Chile saltpeter (UK: Chile saltpetre), is a

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

, the naturally occurring form of sodium nitrate, NaNO₃. Chemically it is the sodium analogue of

saltpeter Potassium nitrate is a chemical compound with the chemical formula . This alkali metal nitrate salt is also known as Indian saltpetre (large deposits of which were historically mined in India). It is an ionic salt of potassium ions K+ and nitrat ...

. Nitratine crystallizes in the

trigonal In crystallography, the hexagonal crystal family is one of the six crystal families, which includes two crystal systems (hexagonal and trigonal) and two lattice systems (hexagonal and rhombohedral). While commonly confused, the trigonal crysta ...

system, but rarely occurs as well formed crystals. It is isostructural with

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

. It is quite soft and light with a

Mohs hardness The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by t ...

of 1.5 to 2 and a

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...

of 2.24 to 2.29. Its

refractive indices In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...

are nω=1.587 and nε=1.336. The typical form is as coatings of white, grey to yellowish brown masses. The rare crystals when found typically have the scalenohedral form of the

structure. It is found only as an efflorescence in very dry environments. It is very soluble in water such that it is

deliquescent Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...

and will absorb water out of the air and turn into a ''puddle'' of sodium nitrate solution when exposed to humid air. Nitratine was once an important source of nitrates for fertilizer and other chemical uses including

fireworks Fireworks are a class of Explosive, low explosive Pyrotechnics, pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a l ...

. It has been known since 1845 from occurrences in the

Confidence Hills The Confidence Hills are a mountain range in the Mojave Desert, in southern Inyo County, California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area ...

, Southern

Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the Highest temperature recorded on Earth, hottest place on Earth. Death Valley's Badwater Basin is the ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

and the

Atacama Desert The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in th ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

. It is still used in

organic farming Organic farming, also known as ecological farming or biological farming,Labelling, article 30 o''Regulation (EU) 2018/848 of the European Parliament and of the Council of 30 May 2018 on organic production and labelling of organic products and re ...

(where Haber–Bosch ammonia is forbidden) in the US, but prohibited in international organic agriculture. The Saltpeter War (1480-1510) and the

War of the Pacific The War of the Pacific ( es, link=no, Guerra del Pacífico), also known as the Saltpeter War ( es, link=no, Guerra del salitre) and by multiple other names, was a war between Chile and a Bolivian–Peruvian alliance from 1879 to 1884. Fought ...

(1879-1884) were fought over the control of saltpeter deposits.

References

External links

Nitratine page
on mindat.org
Nitratine page on webmineral.com

{{Authority control Sodium minerals Nitrate minerals Saltpeter works Trigonal minerals Minerals in space group 167

See also

References

External links