Periclase

Periclase, also Periklasit, chemically magnesium oxide, is a rarely occurring mineral from the mineral class of oxides and hydroxides. It crystallizes in the cubic crystal system with the chemical composition of MgO and forms small octahedral, or cuboctahedral rarely dodecahedral crystals of white, green or black by inclusions and color.

Special Features

Powder coating is periclase soluble in water and causes a reaction in alkaline magnesium hydroxide.

Etymology and history

The mineral was first discovered in 1840 by Arcangelo Scacchi on Monte Somma, near the Mount Vesuvius in Italy. It was named after the Greek περικλάω ( leave ) because of its perfect cubic cleavage.

Classification

In the classification by Strunz periclase is counted among the oxides with a ratio of metal to oxygen of 2:1 or 1:1. After the 8th edition forms a group together with calcium oxide, Monteponit, bunsenite, Murdochit, Manganosit and wustite. In the 9th edition it forms with the same minerals except the Murdochit a subset of the oxides with a ratio of metal to oxygen of 1:1 and small to medium-sized cations ( Periklasgruppe ).

In the classification by Dana it forms with calcium oxide, Monteponit, bunsenite, Maganosit, wustite and Hongquiit the Periklasgruppe, a subgroup of the simple oxides with a cation charge of 2 .

Modifications and varieties

With ferropericlase eisenhalitge a variety of Periklases is known. Also referred to as artificial periclase Lavernit.

Education and Locations

Periclase formed by metamorphism under high temperature magnesium-containing dolomite and limestone. It is depending on the locality associated with forsterite and magnesite, brucite, hydromagnesite and Ellestadit or Fluorellestadit, lime, Magnesioferrit, hematite, and anhydrite Srebrodolskit.

In addition to the type locality was found periclase among others in Predazzo in Italy, Carlingford in Ireland, Broadford and Camas Mòr in Scotland, León in Spain, Mayener Bellerberg in the Eifel ( Germany ), Nordmark and Långban in Sweden, Kopeisk in Russia, Crestmore, Tompstone and Gabbs in the United States, in Canada and Oka Cowell in Australia.

Crystal structure

Periclase crystallizes in the cubic crystal system with the space group with the lattice parameters a = 4.21 Å and four formula units per unit cell ( sodium chloride structure).