Periclase is a magnesium mineral that occurs naturally in contact metamorphic rocks and is a major component of most basic refractory bricks. It is a cubic form of magnesium oxide (Mg O). In nature it usually forms a solid solution with wüstite (FeO) and is then referred to as ferropericlase or magnesiowüstite. [6]

Periclase is a rare magnesium oxide mineral. It is usually found as a component of metamorphosed dolomitic limestones. May be associated with pyrometamorphism (e.g., coal fires). It can hydrate and alter to Brucite and other magnesium minerals by action of the humidity in normal atmospheric conditions.

periclase, magnesium oxide mineral (MgO) that occurs as colourless to grayish, glassy, rounded grains in marble and in some dolomitic limestones, where it formed by the metamorphosis of dolomite at high temperatures.

Periclase (MgO) is cubic (space group Fm 3 ¯ m) with a perfect {001} cleavage. It is found in metamorphosed limestones and dolomites. The name is from the Greek peri, around, and klasis, fracture, and refers to the perfect cleavage.

Periclase. Comments: Green nickel-rich periclase on matrix. Location: Ronneburg U deposit, Gera district, Thuringia, Germany. Scale: Picture size 1.5 mm. © Thomas Witzke / Abraxas-Verlag

- Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties).

Lecture Notes - Mineralogy - Periclase Structure • In lab we determined the unit cell for a crystal of synthetic periclase (MgO). Because periclase is cubic, only one lattice parameter (a) is needed to completely specify the size and shape of the unit cell. We found that a = 0.421 nm (= 4.21 Å). Based on this measurement, the volume ( V)

A product of the high-temperature metamorphism of magnesian limestones and dolostone. Association: Forsterite, magnesite (Monte Somma, Italy); brucite, hydromagnesite, ellestadite (Crestmore quarry, California, USA); fluorellestadite, lime, periclase, magnesioferrite, hematite, srebrodolskite, anhydrite (Kopeysk, Russia).

Periclase, whose crystal structure resembles that of rock salt, crystallizes in the isometric system to form cubic and octahedral crystals as well as irregular grains; cleavage is perfect along the cube.

This BSE image (from an EPMA session) shows zoned slightly Zn-enriched periclase-wüstite solid solution crystals, sitting in a metacabonate slag of the "nutshell" type; the ferropericlase is the main constituent of inner, macroscopically white zones (may be associated with spurrite and some Zn-Fe likely hexagonal sulphides), while the outer, ...