Periclase

Periclase
Periclase
General
Category Oxide minerals
Chemical formula MgO
Strunz classification 04.AB.25
Crystal symmetry Cubic 4/m 3 2/m
Unit cell 4.21 Å Z=4
Identification
Color Colorless, grayish white, yellow, brownish yellow, green, black
Crystal habit Granular, generally occurs as anhedral to subhedral octahedral crystals in matrix
Crystal system Isometric - Hexoctahedral
Cleavage

{001} perfect; {111} imperfect, may exhibit parting on

{011}
Fracture Conchoidal
Tenacity Brittle
Mohs scale hardness 6
Luster Vitreous
Streak White
Diaphaneity Transparent to translucent
Specific gravity 3.56–3.68 (meas.) 3.58 (calc.)
Optical properties Isotropic
Refractive index n = 1.735–1.745
Other characteristics Fluorescent, long UV=light yellow.
References [1][2][3]

Periclase occurs naturally in contact metamorphic rocks and is a major component of most basic refractory bricks. It is a cubic form of magnesium oxide (MgO).

It was first described in 1840 and named from the Greek περικλάω (to break around) in allusion to its cleavage. The type locality is Monte Somma, Somma-Vesuvius Complex, Naples Province, Campania, Italy.[3]

The old term for the mineral is magnesia. Stones from the Magnesia region in ancient Anatolia contained both magnesium oxide and hydrated magnesium carbonate as well as iron oxides (such as magnetite). Thus these stones, called Stones from Magnesia in antiquity, with their unusual magnetic properties were the reason the terms magnet and magnetism were coined.

Periclase is usually found in marble produced by metamorphism of dolomitic limestones. It readily alters to brucite under near surface conditions.[3]

In addition to its type locality, it is reported from Predazzo, Tyrol, Austria; Carlingford, County Louth, Ireland; Broadford, Skye and the island of Muck, Scotland; León, Spain; the Bellerberg volcano, Eifel district, Germany; Nordmark and Långban, Varmland, Sweden; and Kopeysk, southern Ural Mountains, Russia. In the USA it occurs at the Crestmore quarry, Riverside County, California; Tombstone, Cochise County, Arizona; Gabbs district, Nye County, Nevada. In Canada, it occurs at Oka, Quebec and in Australia, west of Cowell, Eyre Peninsula, South Australia.[1]

References


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Look at other dictionaries:

  • Périclase — Catégorie IV : oxydes et hydroxydes[1] Général Classe de Strunz 04.AB.25 Formule brute Mg …   Wikipédia en Français

  • périclase — 1. (pé ri kla z ) s. f. Terme de grammaire grecque. La modification du son représentée par l accent circonflexe, qui consistait en une élévation suivie d un abaissement de la voix. Y avait il en effet sur la même syllabe intensité de la voix d… …   Dictionnaire de la Langue Française d'Émile Littré

  • Periclase — Per i*clase, Periclasite Per i*cla site, n. [Pref. peri + Gr. ? to break.] (Min.) A grayish or dark green mineral, consisting essentially of magnesia (magnesium oxide), occurring in granular forms or in isometric crystals. [1913 Webster] …   The Collaborative International Dictionary of English

  • périclase — ● périclase nom féminin Oxyde naturel de magnésium, cubique, de formule MgO …   Encyclopédie Universelle

  • periclase — /per i klays , klayz /, n. a cubic mineral, native magnesia, MgO, occurring usually in metamorphosed dolomite. [1835 45; < G Periklas < NL periclasia, equiv. to peri PERI + Gk klás(is) a breaking (cf. CLASE) + ia IA] * * * ▪ mineral… …   Universalium

  • periclase — noun A cubic crystalline form of magnesium oxide (MgO) …   Wiktionary

  • periclase — Смотри Периклаз …   Энциклопедический словарь по металлургии

  • periclase — [ pɛrɪkleɪz, s] noun a colourless mineral consisting of magnesium oxide, occurring chiefly in marble and limestone. Origin C19: from mod. L. periclasia, erroneously from Gk peri utterly + klasis breaking (because it cleaves perfectly) …   English new terms dictionary

  • periclase — peri·clase …   English syllables

  • periclase — /ˈpɛrikleɪz/ (say pereeklayz), / eɪs/ (say ays) noun naturally occurring magnesium oxide. {German periklas} …  

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