Prehnita

CaracterÃsticas generales

FÃ³rmula: Ca₂Al₂Si₃O₁₀(OH)₂
Sistema de cristalizaciÃ³n: OrtorrÃ³mbico
Lustre: VÃtreo - perlado
Color: Verde amarillento, amarillo, blanco, gris o incoloro
Dureza: 6-6,5
Rareza: extendido
CaracterÃsticas distintivas: HÃ¡bito cristalino, color, exfoliaciÃ³n, dureza y minerales asociados.

FotografÃas

En la galerÃa de fotografÃas dispones de 3 fotografÃas de Prehnita

Prehnita (3 de 3)

Prehnita (2 de 3)

Prehnita (1 de 3)

FormaciÃ³n y ambiente

Es un tÃpico mineral hidrotermal secundario, producido a partir de la alteraciÃ³n de plagioclasas bÃ¡sicas de gabros y anfibolitas. Es un mineral secundario formado en las grietas de las rocas volcÃ¡nicas bÃ¡sicas, siempre que sean ricas en calcio. TambiÃ©n en rocas Ãgneas y menos frecuentemente como producto del metamorfismo de grado bajo. En todas ellas, puede aparecer rellenado cavidades en la roca en forma de geoda o tapizando fracturas.

Rocas hidrotermalmente alteradas

Hidrotermal, metamÃ³rfico.

Propiedades fisicas

HÃ¡bito: EstalactÃcito, reniforme, laminar, granular, globular o columnar.

Lustre: VÃtreo - perlado

Transparencia: TranslÃºcido, SubtranslÃºcido

Color: Verde amarillento, amarillo, blanco, gris o incoloro

Color en secciÃ³n fina: Incolora

Raya: Incolora

Dureza (Mohs): 6-6,5

Tenacidad: FrÃ¡gil

ExfoliaciÃ³n::

Primera exfoliaciÃ³n: Notable en [001]
Segunda exfoliaciÃ³n: Notable
Tercera exfoliaciÃ³n: Notable

Fractura: Desigual

Densidad: 2,8-3 g/cm³ (medida) | 2,82 g/cm³ (calculada)

CristalografÃa

Sistema cristalino:

OrtorrÃ³mbico

Clase (H-M): 1m (222) - Disfenoidal

Grupo espacial: P2cm

ParÃ¡metros de la celda: a=4,61Ã… b=5,47Ã… c=18,48Ã…

Volumen de unidad de celda: V 466Ã…

Z: 2

DifracciÃ³n de Rayos X:

DifracciÃ³n de Rayos X
D(hkl)	Intensidad
2,55	100
3,08	100
3,48	90

Propiedades Ã³pticas

Tipo: Biaxial (+)

Valores RI: n_Î±= 1,61 - 1,637; n_Î²= 1,615 - 1,647; n_Î³= 1,632 - 1,67

2V: medida: 65Âº - 69

MÃ¡xima birrefringencia: Î´ = 0,033

DispersiÃ³n: De dÃ©bil a fuerte

Pleocroismo: Pleiocroico
X: Incoloro
Y: Incoloro
Z: Incoloro

Propiedades quÃmicas

FÃ³rmula: Ca₂Al₂Si₃O₁₀(OH)₂

Elementos quÃmicos: Ca, Al, Si, O, H

ComposiciÃ³n quÃmica: H: 0,25%, Al: 13,65%, Ca: 20,27%, Si: 21,31%, O: 44,51%,

Tests quÃmicos

Fusibilidad: 2; Mineral tipo: Natrolita; Punto de fusiÃ³n: 800ÂºC; Funde con mechero de gas
ReacciÃ³n a los Ã¡cidos: Se descompone en HCl con la formaciÃ³n de un sÃlice gelatinoso.
Ensayos en tubo cerrado: Libera agua solo con llama roja.
FormaciÃ³n de sublimados: Se funde originando un cristal blanco

Otras propiedades

Relaciones con otros minerales

Minerales acompaÃ±antes:

minerales

Apofilita

FÃ³rmula:
Sistema de cristalizaciÃ³n: Tetragonal
Dureza: 4,5-5
Color: Los cristales son por lo general incoloros y transparentes, o bien blancos y translÃºcidos u opacos, pero los mÃ¡s buscados son los amarillos, violetas, rosados o verdes,
Raya: Blanco
Brillo: VÃtreo - perlado

minerales

Localidades

Cape of Good Hope, South Africa - Localidad tipo.
Cygnet, Tasmania, Australia
Garrawilla, New South Wales, Australia
Prospect Hill, New South Wales, Australia
Wave Hill, Northern Territory, Australia
Krasne, Sumperk, Maehren, Czech Republic
Libodrice, Kutna Hora, Stredocesky, Czech Republic
Copt Hill Quarry, Weardale, Co. Durham, England
Croft quarry, Leicestershire, England
Dean quarry, St. Keverne, Cornwall, England
Disgwylfa Hill, Moreswood, Shropshire, England
Force Garth Quarry, Teesdale, Co. Durham, England
Ghostcroft mine, Mullion, The Lizard, Cornwall, England
Levant mine, Pendeen, St. Just, Cornwall, England
Meldon BR Quarry, Okehampton, Devon, England
New Aplite Quarry, Meldon, Okehampton, Devon, England
Ogo Dour, The Lizard, Cornwall, England
Old Potts Gill mine, Caldbeck Fells, Cumbria, England
Parc Bean Cove, Mullion, The Lizard, Cornwall, England
Pentire Cliffs, St. Minver, Cornwall, England
Porthoustock quarry, St. Keverne, Cornwall, England
Predannack Head, The Lizard, Cornwall, England
Rosecommon Cliffs, Botallack, St. Just, Cornwall, England
Squilver Quarry, Dysgwylfa Hill, Shropshire, England
Stamps and Jowl Zawn, Roscommon Cliff, St. Just, Cornwall, England
Thurstaston Beach, Wirral, Merseyside, England
Artenberg quarry, Kinzigtal, Baden-Wuerttemberg, Germany
BÃ¤rensteinbruch quarry, Radautal, Bad Harzburg, Harz Mts, Sachsen, Germany
Hechtsberg quarry, Kinzigtal, Baden-Wuerttemberg, Germany
Heimberg quarry, MÃ¶ncheholz, Langelsheim, Harz Mts, Sachsen, Germany
Huneberg quarry, Bad Harzburg, Harz Mts, Sachsen, Germany
Nesselgrund quarry, Schnellbach, Bad Salzungen, ThÃ¼ringen, Germany
St. Andreasberg, Hartz Mts, Niedersachsen, Germany
Wormekthal, Harz Mtns., Niedersachsen, Germany
Bombay-Malad Quarry, Maharashtra, India
Poona, Maharashtra, India
Camaderry Mountin, Gendalough, Co. Wicklow, Ireland
Baveno, Lago Maggiore, Piedmont, Italy
Molana Quarry, Val Graveglia, Liguria, Italy
Monte Penna, Parmense Apennine, Parma, Italy
Val Graveglia, Liguria, Italy
Fuka mine, Bicchu-cho, Kawakami, Okayama Pref., Japan
Sarbay silver mine, Rudni, Kusteni Oblast, Kazakhstan
BuÃ¶, Arendal, Froland, Aust-Agder, Norway
Evje-Ivedal, Iveland, Aust-Agder, Norway
Kongsberg, Buskerud, Norway
Afrikanda, Murmansk Oblast, Lovozero massif, Kola Peninsula, Russia
Aldan Shield, Yakutiya, Siberia, Russia
Bakhchisaray, Crimea, Russia
Dal'negorsk, Primorskiy Kray, Russia
Dodo mine, Polar Urals, Tyumen Oblast, Russia
Polar Urals, Tyumen Oblast, Russia
An Gearna, Ben More, Isle of Mull, Scotland
Ben More, Isle of Mull, Scotland
Binhill Quarry, Huntly, Aberdeenshire, Scotland
Bishopton, Renfrewshire, Scotland
Borrow-Pit (by M8 motorway), Bishopton, Renfrewshire, Scotland
Boyleston Quarry, Barrhead, Glasgow, Scotland
Carsaig Bay, Carsaig, Isle of Mull, Scotland
Creag Brimishgan, Loch Na Keal, Isle of Mull, Scotland
Creag Thor, Isle of Mull, Scotland
Eas a Bradain, Luib, Isle of Skye, Scotland
Hartfield Moss, Strathclyde, Scotland
Loanhead quarry, near Beith, Strathclyde, Scotland
Marsco, Sligachan, Isle of Skye, Scotland
Orrock Quarry, Kirkcaldy, Fife, Scotland
Pitscurries Quarry, Pitcaple, Aberdeenshire, Scotland
Salen, Isle of Mull, Scotland
Scarisdale Wood (beach), Loch na Keal, Knock, Isle of Mull, Scotland
Sgurr nan Cearcall, Isle of Skye, Scotland
Sligachan quarry, Sligachan, Isle of Skye, Scotland
Messina, Transvaal, South Africa
Palabora mine, Loolekop, Transvaal, South Africa
Arvigo, Val Calanca, GraubÃ¼nden, Switzerland
Motte Naira, Tavetsch, GraubÃ¼nden, Switzerland
Saas Fee, Valais, Switzerland
Arlington Quarry etc, Leesburg, Loudoun Co., Virginia, USA
Bayer-Mingolla Quarry, Ashland, Norfolk Co., Massachusetts, USA
Bellows Falls, Windham Co., Vermont, USA
Bisbee, Cochise Co., Arizona, USA
Blue Berry Mt., Woburn, Middlesex Co., Massachusetts, USA
Bound Brook Quarry, Bridgewater, Somerset Co., New Jersey, USA
Central mine, Keweenaw Co., Michigan, USA
Centreville, Fairfax Co., Virginia, USA
Chantilly Quarry, Arcola, Loudoun Co., Virginia, USA
Cloverdale Russian River Area, Mendocino Co., California, USA
Conklin quarry, Lincoln, Providence Co., Rhode Island, USA
Copper Harbor, Lake Manganese, Keeweenaw Co., Michigan, USA
Copper Harbour, near Lake Manganese, Keweenaw Co., Michigan, USA
Copper Queen Mine, Bisbee, Cochise Co., Arizona, USA
Cornwall, Lebanon Co., Pennsylvania, USA
Crestmore Quarry, Crestmore, Riverside Co., California, USA
Durham Quarry, Wake Co., North Carolina, USA
Fairfax Co., Virginia, USA
Fairfax Quarry, Centreville, Fairfax Co., Virginia, USA
Fanwood Quarry, Plainfield, New Jersey, USA
Farmingtom, Hartford Co., Connecticut, USA
Farmington, Hartford Co., Connecticut, USA
Foote Spodumene Mine, Kings Mountain, Cleveland Co., North Carolina, USA
Garret Mountain Quarries, Paterson, Passaic Co., New Jersey, USA
Goose Creek Quarry, Loudoun Co., Virginia, USA
Great Notch Quarry, Little Falls, Passaic Co., New Jersey, USA
Hampden quarry, Westfield, Hampden Co., Massachusetts, USA
Hunting Hill quarry, Rockville, Montgomery Co., Maryland, USA
Iriquois Mine, Ahmeek, Keweenaw Co., Michigan, USA
Italian Mt. Area, Aspen, Gunnison Co., Colorado, USA
Jacksonwald, Berks Co., Pennsylvania, USA
Jensen Quarry, Riverside Co., California, USA
Keweenawan copper deposit, Lake Superior, Michigan, USA
Keystone Quarry, Cornog, Chester Co., Pennsylvania, USA
Lane & Sons Traprock quarrys, Westfield, Hampden Co., Massachusetts, USA
Lane Quarry, Westfield, Hampden Co., Massachusetts, USA
Laurel Hill (Snake Hill), Secaucus/Bergen Hill Area, Hudson Co., New Jersey, USA
Liberty Bell and Washington Pass, Okanogan Co., Washington, USA
Loudon Co., Virginia, USA
Lower New Street quarry, Paterson, Passaic Co., New Jersey, USA
Luning, Mineral Co., Nevada, USA
Manville quarry, Cumberland, Providence Co., Rhode Island, USA
Martin Marietta Quarry, Hickory, Catawba Co., North Carolina, USA
McKiernan & Bergin quarry, Paterson, Passaic Co., New Jersey, USA
Millington quarry, Millington, Somerset Co., New Jersey, USA
Montclair Quarry, Montclair, Passaic Co., New Jersey, USA
Mt Belvidere mines, Lowell & Eden Mills, Orleans Co., Vermont, USA
No. 4 Quarry, Harrisville, Lewis Co., New York, USA
No.4 Wollastonite quarry, near Harrisville, Lewis Co., New York, USA
O&G quarry, Southbury, New Haven Co., Connecticut, USA
Osceola/Mohawk/Iroquois/Clark/Delaware Mine etc, Keweenaw Peninsula, Michigan, USA
Paterson, Passaic Co., New Jersey, USA
Perry Trapprock locality, Perry, Washington Co., Maine, USA
Phoenix mine, near Eagle Harbor, Keweenaw Co., Michigan, USA
Pidgeon Point, Cook Co., Minnesota, USA
Portage Lake Lava area, Keweenaw Co., Michigan, USA
Prospect Park Quarry, Haledon, Passaic Co., New Jersey, USA
Quabbin Aqueduct, Hardwick, Worcester Co., Massachusetts, USA
Quarry, Rocky Hill, Somerset Co., New Jersey, USA
Roncari quarry, East Granby, Hartford Co., Connecticut, USA
Route 80 roadcut, Passaic Co., New Jersey, USA
Santa Rita Peak, Hernandez, San Benito Co., California, USA
Shaft #10, Quabbin Aquaduct, Hardwick, Worcester Co., Massachusetts, USA
Somerville, Middlesex Co., Massachusetts, USA
Stinson Beach Area, Marin Co., California, USA
Tilly Foster Mine, Brewster, Putnam Co., New York, USA
Trap rock Quarry, Chesire, New Haven Co., Connecticut, USA
Unionville, Chester Co., Pennsylvania, USA
Upper New Street Quarry, Paterson, Passaic Co., New Jersey, USA
Warner, Merrimack Co., New Hampshire, USA
Wilbur Springs, Colusa Co., California, USA
Woodbury traprock quarry, Litchfield Co., Connecticut, USA
Llanelwedd Quarry, Builth Wells, Powys, Wales

Usos y apliaciones

Se usa poco, como piedra ornamental, aunque puede ser tallada como gema semipreciosa. El principal interÃ©s es el cientÃfico y coleccionÃstico.

BibliografÃa y mÃ¡s informaciÃ³n

Canadian Mineralogist, vol. 25, p.707, (1987)
European Journal of Mineralogy, vol. 2, p.731-734, (1990)

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Prehnita

CaracterÃ­sticas generales

FotografÃ­as

FormaciÃ³n y ambiente

Propiedades fisicas

CristalografÃ­a

Propiedades Ã³pticas

Propiedades quÃ­micas

Tests quÃ­micos

Otras propiedades

Relaciones con otros minerales

Minerales acompaÃ±antes:

Minerales acompaÃ±antes

Yacimientos y localidades de interÃ©s

Localidades

Usos y apliaciones

BibliografÃ­a y mÃ¡s informaciÃ³n

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