Formula: MgO simple oxide
Specific gravity: 3.55 to 3.57
Colour: Colourless, grayish white, yellow, brownish yellow, green, black
Solubility: Insoluble in water, soluble in hydrochloric, nitric and sulphuric acid
Periclase is found as a product of contact metamorphism of
It is a mineral of the amphibolite facies.
During the progressive metamorphism of silica-rich dolostones the following approximate sequence of mineral formation is often found, beginning with the lowest temperature product: talc, tremolite, diopside, forsterite, wollastonite, periclase, monticellite
brucite to periclase and H2O
Mg(OH)2 ⇌ MgO + H2O
The equilibrium temperature for this reaction at 10 kbar pressure is about 840oC (granulite facies), with the equilibrium to the right at higher temperatures, and to the left at lower temperatures (for the same pressure).
Common impurity: Fe