Mindat Logo

Prehnite

This page kindly sponsored by Gerald & Linna Pauley



Formula:
Ca
 
2
Al
 
2
Si
 
3
O
 
10
(OH)
 
2
System:OrthorhombicColour:Colourless to gray to ...
Lustre:Vitreous, PearlyHardness:6 - 6½
Name:Named in 1788 by Abraham Gottlieb Werner in honor of the Dutch Colonel, Hendrik von/van Prehn [July 31/August 2, 1733 Cape of Good Hope Colony - August, 1785 Heilbronn, Wurttemberg {Germany}], who is credited with discovering the mineral in 1774 at the Cape of Good Hope in South Africa. Von Prehn was a governor of Cape of Good Hope (1779-1780) until he was dismissed. He was a naturalist and mineral collector who brought the the first specimens of his namesake mineral to Europe. It is unknown how the mineral came to the attention of Werner. A considerable mystique and folklore has surrounded Prehn and prehnite. The appelation "von" was supposedly bestowed on Prehn for his military service during the Seven Year's War, but there are no printed records available to substantiate the claim. It has been claimed that prehnite was the mineral named for a person. In 1813, Richard Chenevix wrote a lengthy article (100+ pages) decrying the naming of minerals for people.)


Visit gemdat.org for gemological information about Prehnite. Currently in public beta-test.

Classification of Prehnite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/G.07-30
Nickel-Strunz 10th (pending) edition ID:9.DP.20

9 : SILICATES (Germanates)
D : Inosilicates
P : Transitional ino-phyllosilicate structures
Dana 8th edition ID:72.1.3.1

72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
1 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with 4-membered rings
Hey's CIM Ref.:16.9.10

16 : Silicates Containing Aluminum and other Metals
9 : Aluminosilicates of Ca
mindat.org URL:http://www.mindat.org/min-3277.html
Please feel free to link to this page.

Type Occurrence of Prehnite

Type Locality:Karoo dolerites, Cradock, Chris Hani District, Eastern Cape Province, South Africa
Year of Discovery:1788

Occurrences of Prehnite

Geological Setting:A secondary mineral in mafic volcanic rocks, low grade metamorphic mineral.

Physical Properties of Prehnite

Lustre:Vitreous, Pearly
Diaphaneity (Transparency):Translucent
Comment:Pearly on cleavage {001}
Colour:Colourless to gray to yellow, yellow-green or white
Streak:White
Hardness (Mohs):6 - 6½
Tenacity:Brittle
Cleavage:Distinct/Good
Good on {001}, poor on {110}
Fracture:Irregular/Uneven
Density (measured):2.8 - 2.95 g/cm3
Density (calculated):2.9 g/cm3

Crystallography of Prehnite

Crystal System:Orthorhombic
Class (H-M):mm2 - Pyramidal
Cell Parameters:a = 4.646(2) Å, b = 5.491(3) Å, c = 18.52(3) Å
Ratio:a:b:c = 0.846 : 1 : 3.373
Unit Cell Volume:V 472.47 ų (Calculated from Unit Cell)
Z:2
Morphology:Uncommon crystals, aggregates are fanlike, reniform, globular, stalagtitic, granular, compact.
Twinning:Fine lamellar
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.
X-Ray Powder Diffraction:
d-spacingIntensity
3.48 (90)
3.28 (60)
3.08 (100)
2.55 (100)
2.37 (40)
2.31 (40)
1.77 (70)
(

Optical Data of Prehnite

Type:Biaxial (+)
RI values: nα = 1.611 - 1.632 nβ = 1.615 - 1.642 nγ = 1.632 - 1.665
2V:Measured: 64° to 70°, Calculated: 58° to 68°
Maximum Birefringence:δ = 0.021 - 0.033

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:weak r > v

Chemical Properties of Prehnite

Formula:
Ca
 
2
Al
 
2
Si
 
3
O
 
10
(OH)
 
2
Simplified for copy/paste:Ca2Al2Si3O10(OH)2
Essential elements:Al, Ca, H, O, Si
All elements listed in formula:Al, Ca, H, O, Si
Common Impurities:Ti,Fe,Mg,Na,K,H2O

Relationship of Prehnite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
9.DP.05Meliphanite
(Ca,Na)
 
2
(Be,Al)[Si
 
2
O
 
6
(OH,F)]
9.DP.15Leucosphenite
BaNa
 
4
Ti
 
2
B
 
2
Si
 
10
O
 
30
9.DP.25Amstallite
CaAl(Si,Al)
 
4
O
 
8
(OH)
 
4
· (H
 
2
O,Cl)
9.DP.30Kvanefjeldite
Na
 
4
(Ca,Mn)(Si
 
3
O
 
7
)
 
2
(OH)
 
2
9.DP.35Lemoynite
(Na,K)
 
2
CaZr
 
2
Si
 
10
O
 
26
· 5H
 
2
O
9.DP.35Natrolemoynite
Na
 
4
Zr
 
2
Si
 
10
O
 
26
•9H
 
2
O
9.DP.40Altisite
Na
 
3
K
 
6
Ti
 
2
Al
 
2
Si
 
8
O
 
26
Cl
 
3
Related Minerals - Hey's Index Grouping:

- +
16.9.1Gehlenite
Ca
 
2
Al(AlSiO
 
7
)
16.9.2Anorthite
CaAl
 
2
Si
 
2
O
 
8
16.9.3Yoshiokaite
(Ca,Na)[Al(Al,Si)O
 
4
]
16.9.4Svyatoslavite
CaAl
 
2
Si
 
2
O
 
8
16.9.5Dmisteinbergite
CaAl
 
2
Si
 
2
O
 
8
16.9.6Grossular
Ca
 
3
Al
 
2
(SiO
 
4
)
 
3
16.9.7Vuagnatite
CaAl(SiO
 
4
)(OH)
16.9.8Zoisite
{Ca
 
2
}{Al
 
3
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
16.9.9Clinozoisite
{Ca
 
2
}{Al
 
3
}(Si
 
2
O
 
7
)(SiO
 
4
)O(OH)
16.9.11Kamaishilite
Ca
 
2
(Al
 
2
SiO
 
6
)(OH)
 
2
16.9.12Bicchulite
Ca
 
2
(Al
 
2
SiO
 
6
)(OH)
 
2
16.9.13Margarite
CaAl
 
2
(Al
 
2
Si
 
2
O
 
10
)(OH)
 
2
16.9.14Chantalite
CaAl
 
2
(SiO
 
4
)(OH)
 
4
16.9.15Cebollite
Ca
 
5
Al
 
2
(SiO
 
4
)
 
3
(OH)
 
4
16.9.17Katoite
Ca
 
3
Al
 
2
(SiO
 
4
)
 
3-x
(OH)
 
4x
16.9.18Lawsonite
CaAl
 
2
(Si
 
2
O
 
7
)(OH)
 
2
· H
 
2
O
16.9.19Parthéite
CaAl
 
2
Si
 
2
O
 
8
· 2H
 
2
O
16.9.20Wairakite
Ca(Al
 
2
Si
 
4
O
 
12
) · 2H
 
2
O
16.9.21Vertumnite
Ca
 
4
Al
 
4
Si
 
4
O
 
6
(OH)
 
24
· 3H
 
2
O
16.9.22Scolecite
CaAl
 
2
Si
 
3
O
 
10
· 3H
 
2
O
16.9.23Laumontite
CaAl
 
2
Si
 
4
O
 
12
· 4H
 
2
O
16.9.24Yugawaralite
CaAl
 
2
Si
 
6
O
 
16
· 4H
 
2
O
16.9.25Gismondine-Ca
CaAl
 
2
Si
 
2
O
 
8
· 4H
 
2
O
16.9.26Epistilbite
CaAl
 
2
Si
 
6
O
 
16
· 5H
 
2
O
16.9.27Goosecreekite
Ca[Al
 
2
Si
 
6
O
 
16
] · 5H
 
2
O
16.9.28Cowlesite
CaAl
 
2
Si
 
3
O
 
10
· 6H
 
2
O
16.9.30Stellerite
Ca[Al
 
2
Si
 
7
O
 
18
] · 7H
 
2
O
16.9.31Strätlingite
Ca
 
2
Al
 
2
SiO
 
7
· 8H
 
2
O
16.9.32Amstallite
CaAl(Si,Al)
 
4
O
 
8
(OH)
 
4
· (H
 
2
O,Cl)

Other Names for Prehnite

Synonyms:
Adelite (of de Fourestier)AdiliteAedeliteÆdelite (of Walmstedt)Aedilite
BostrichitesChiltoniteChrysolite (of Sage)CoupholitePrehnitoid (of Bechi)
Other Languages:
Dutch:Prehniet
French:Chrysolite du Cap
German:Prehnit
Adilit
Aedelit
Aedilit
Chiltonit
Coupholit
Edelit
Hungarian:Prehnit
Italian:Prehnite
Japanese:ぶどう石
Polish:Prehnit
Russian:Пренит
Simplified Chinese:葡萄石
Spanish:Prehnita
Adilita
Aedelita
Aedilita
Chiltonita
Coupholita
Edelita
Swedish:Ædelforsit (of Walmstedt)
Varieties:
Patricianite

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Prehnite

Reference List:

- +
F. Aumento (1968): The space group of prehnite. Can. Mineral. 9, 485-492.

European Journal of Mineralogy (1990): 2: 731-734.

Canadian Mineralogist (1987): 25: 707.

Mindat.org articles about Prehnite

Article entries:
Prospect (Prospect Hill), NSW, AuKeith Compton

Best Localities for Prehnite

Best of Species:Prehnite

Internet Links for Prehnite

Search Engines:
  • Look for Prehnite on Google
  • Look for Prehnite images on Google
  • External Links:
  • Look for Prehnite on Webmineral
  • Look for Prehnite on Athena Mineralogy
  • Look for Prehnite on Wikipedia
  • Look for Prehnite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Prehnite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • The Arkenstone - Fine Minerals
  • Buy fine minerals and gemstones from Pala International
  • Mineral Classics - Worldwide Collector Quality Minerals and Gems
  • Top quality minerals from Kristalle of California
  • Rare and Unusual minerals at Mineralogical Research Company
  • Buy RARE Minerals from Rocks of Africa
  • Buy from David K Joyce minerals
  • rare and unusual minerals mainly crystallized
  • Fabre Minerals - search for Prehnite specimens
  • Find Prehnite on www.crystalclassics.co.uk
  • Buy from Dave Bunk Minerals
  • Fine Minerals from Weinrich Minerals, Inc.
  • Specimens:The following Prehnite specimens are currently listed for sale on minfind.com.

    Localities for Prehnite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    矿物 and/or 产地  
    谷歌搜索  
    版权所有© Jolyon Ralph 和周兰怡 1993年至2014年 网站地图 产地,矿物及照片的数据是有獨立各別的版权。欲求更多信息,请联系本站长 网站托管和开发 Jolyon Ralph。 Mindat.org是一个致力于免费提供所有有関於矿物学上所有信息資源的网站。 Mindat資訊是依靠全球成千過萬的成员和支持者的贡献。 Mindat不設提供矿物、岩石等物品出售。 如果阁下想參与提供添加有関矿物資訊或提高本数据库质量,請点击这里进行注册。.
    Current server date and time: 2014.9.30 01:04:04
    Mineral and Locality Search
    Mineral:
    and/or Locality:
    Options
    Fade toolbar when not in focusFix toolbar to bottom of page
    Hide Social Media Links
    Slideshow frame delay seconds