Sylvite

Sylvite is a rarely occurring mineral from the mineral class of " halides ". It crystallizes in the cubic crystal system with the composition of KCl, is so chemically speaking potassium chloride.

Sylvite usually develops cubic or octahedral crystals and combinations. In its pure form it is colorless and transparent. However, it can also appear white and accept by foreign admixtures a light gray, light blue, yellowish to reddish or violet color by multiple light scattering due to lattice defects or polycrystalline training.

Sylvite is a rock -forming mineral that is known as sylvite and halite along with admixtures of other salt minerals.

Special Features

Due to low levels of the radioactive isotope 40K sylvite is classified as weakly radioactive and has a specific activity of about 16 Bq / g.

Sylvite is water soluble and tastes salty with a bitter aftertaste.

Etymology and history

His final name of the mineral sylvite received in 1832 by François Sulpice Beudant that on it by the Dutch physicist and chemist Franciscus Sylvius ( Franz de le actually Boë or Franciscus Sylvius de le Boë, 1614-1672 ) named, said he actually is the already known and used in medicine KCl preparation Sel de digestis Sylvius relates ( German Digestivsalz of Sylvius ). In his notes Beudant also maintains other hitherto known synonyms for sylvite fixed: muriate de potasse, chlorure de potassium, salt, potash, Sél febrifuge and Sel marin Regenere.

As a type locality applies Vesuvius in Italy.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the sylvite belonged to the mineral class of " halides " and then to the Department of "simple halides ," where he along with Bromargyrit, Carobbiit, Chlorargyrite, Griceit, halite and Villiaumit untitled set III/A.02 formed.

The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the sylvite in the class of " halides " and there in the department of " Simple halides, without H2O". This division, however, is further subdivided by the molar ratio of metal to the respective halo, so that the mineral according to its composition in the subsection "M: X = 1: 3: 1 and 2" is to find where it, along with Carobbiit, Griceit halite and Villiaumit the " Halitgruppe " with the system no. 3.AA.20 forms.

The mainly common in English-speaking classification of minerals according to Dana assigns the sylvite in the class of " halides " and then in the same department. Here he is with halite, Villiaumit, Carobbiit and Griceit in the " Halitgruppe " with the system no. 09:01:01 to find " water clear and hydrated halides with the formula AX" within the subdivision of.

Education and Locations

Potassium salts formed by crystallization of the dissolved substances in the sea water only after the solubility of calcium carbonate, gypsum, and sodium chloride has been reached. Since potassium and magnesium chlorides and sulfates are very easily soluble in water, sea water has almost completely evaporate before potassium salts crystallize. This explains the rarity of Kalisalzlagerstätten compared to rock salt deposits. Sylvite and Sylvinite ( rock from halite, sylvite and some other salt minerals) seem more likely to occur by recrystallization from Carnallititen by saturated sodium chloride solutions, their derivatives sylvite (it) and enriched in magnesium ions are sodium chloride brine. This conversion takes place even today (usually unintentionally ) in Kalisalzlagerstätten place and leads to impairment of the stand in the extraction residue remaining pillars of carnallitic Kalisalzlagerstätten. Sylvinitbereiche find to be particularly valuable Marginal Facies of the more common carnallititischen potassium salts. Accompanying minerals are halite, carnallite, and others.

As a rather rare mineral sylvite formation can thus be in different localities partly abundant, but overall he is not widespread. So far (as of 2012) are considered to be known around 200 localities.

Localities were formerly among other Staßfurt and Wath, today, for example, Neuhof -Ellers, special Hausen, Zielitz and other Kalisalzlagerstätten in Germany, Beresniki and Solikamsk in the Perm region of Russia, Kalush in Ukraine, in Saskatchewan in Canada and in the Salton Sea USA, and basically in all Kalisalzlagerstätten that degrade sylvite.

Crystal structure

Sylvite crystallizes isotypic with halite in the cubic crystal system in the space group Fm3m ( Raumgruppen-Nr. 225 ) with the lattice parameters a = 6.29 Å and four formula units per unit cell.

Use

Sylvite serves as raw material for the chemical industry, especially for fertilizers. Certain crops (fruit ) tolerate little chloride, potassium sulfate, therefore, be preferable for such fertilizers (eg from polyhalite ).