Prehnite

Prehnite

Prehnite is a phyllosilicate of calcium and aluminium with the formula: Ca2Al(AlSi3O10)(OH)2. Limited Fe3+ substitutes for aluminium in the structure. Prehnite crystallizes in the orthorhombic crystal system. It is brittle with an uneven fracture and a vitreous to pearly lustre. Its hardness is 6-6.5, its specific gravity is 2.80-2.90 and its color varies from light green to grey or white. It is translucent.

Though not a zeolite, it is found associated with them and with datolite, calcite, etc. in veins and cavities of basaltic rocks, sometimes in granites, syenites, or gneisses. It is an indicator mineral of the prehnite-pumpellyite metamorphic facies. It was first discovered in South Africa by Colonel Hendrik Von Prehn, an early Dutch governor of the Cape of Good Hope colony. Prehnite was the first mineral to be named after a person.

Gallery

ee also

*List of minerals
*List of minerals named after people

References

*Hurlbut, Cornelius S.; Klein, Cornelis, 1985, "Manual of Mineralogy", 20th ed., ISBN 0-471-80580-7

External links

* [http://www.prehnite.com.au/specimens.html Prehnite website]
* [http://www.crystal-cure.com/prehnite.html metaphysical meaning and healing properties of prehnite]


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Look at other dictionaries:

  • Prehnite — Catégorie IX : silicates[1] Prehnite La Combe de la Selle, France 7,8  …   Wikipédia en Français

  • PREHNITE — La prehnite cristallise dans le système orthorhombique. Les cristaux aux formes nettes sont rares, ils se présentent sous la forme de tablettes ou de bâtonnets courts. Il existe plusieurs variétés du minéral: la prehnite crêtée formée de lamelles …   Encyclopédie Universelle

  • Prehnite — Prehn ite, n. [So called from the German Colonel Prehn, who first found it.] (Min.) A pale green mineral occurring in crystalline aggregates having a botryoidal or mammillary structure, and rarely in distinct crystals. It is a hydrous silicate of …   The Collaborative International Dictionary of English

  • prehnite — /pray nuyt, pren uyt/, n. a mineral, hydrous calcium aluminum silicate, Ca2Al2Si3O10(OH)2, occurring in light green reniform aggregates or tabular crystals. [1785 95; named after Col. Van Prehn, 18th century Dutchman who brought it from South… …   Universalium

  • prehnite — prenitas statusas T sritis chemija apibrėžtis Mineralas. formulė Ca₂Al[(OH)₂|AlSi₃O₁₀] atitikmenys: angl. prehnite rus. пренит …   Chemijos terminų aiškinamasis žodynas

  • Prehnite-pumpellyite facies — The prehnite pumpellyite facies is a metamorphic facies typical of subseafloor alteration of the oceanic crust around mid ocean ridge spreading centres. It is a metamorphic grade transitional between zeolite facies and greenschist facies… …   Wikipedia

  • prehnite — noun A mineral, a basic calcium, aluminium and iron aluminosilicate, which occurs in stalagtitic aggregates or curved crystals, CaAlSiO(OH) …   Wiktionary

  • prehnite — (prè ni t ) s. f. Substance cristalline composée principalement de silice, d alumine et de chaux, rapportée du cap de Bonne Espérance par le colonel Prehn …   Dictionnaire de la Langue Française d'Émile Littré

  • prehnite — preh·nì·te s.f. TS mineral. minerale raro, di colore biancastro, grigio o verdognolo, costituito da silicato di alluminio e calcio, che si presenta in cristalli riuniti in ammassi e cristallizza nel sistema rombico {{line}} {{/line}} DATA: 1819.… …   Dizionario italiano

  • prehnite — prehn·ite …   English syllables

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