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Halloysite-7Å

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Big Photo

Chatham Co., North Carolina, USA
© Norman King




Formula:
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
System:Monoclinic


Note: halloysite-7Å is not a polytype of halloysite.
It is an approved (grandfathered) species distinct from halloysite-10Å.

A synoym is "metahalloysite."



Classification of Halloysite-7Å

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Nickel-Strunz 10th (pending) edition ID:9.ED.10

9 : SILICATES (Germanates)
E : Phyllosilicates
D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets
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Type Occurrence of Halloysite-7Å

Type Locality:Angleur, Liège, Liège Province, Belgium

Crystallography of Halloysite-7Å

Crystal System:Monoclinic
Class (H-M):m - Domatic
Cell Parameters:a = 5.14Å, b = 8.9Å, c = 14.9Å
β = 101.9°
Ratio:a:b:c = 0.578 : 1 : 1.674
Unit Cell Volume:V 666.97 ų (Calculated from Unit Cell)
Comment:Space group Cc.

Chemical Properties of Halloysite-7Å

Formula:
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
Essential elements:Al, H, O, Si
All elements listed in formula:Al, H, O, Si

Relationship of Halloysite-7Å to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
9.ED.05Dickite
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.05Kaolinite
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.05Nacrite
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.05Odinite
(Fe,Mg,Al,Fe,Ti,Mn)
 
2.4
((Si,Al)
 
2
O
 
5
)(OH)
 
4
9.ED.10Halloysite
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.10Hisingerite
Fe
3+
2
(Si
 
2
O
 
5
)(OH)
 
4
 · 2H
 
2
O
9.ED.15Amesite
Mg
 
2
Al(AlSiO
 
5
)(OH)
 
4
9.ED.15Antigorite
Mg
 
3
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.15Berthierine
(Fe
2+
 
,Fe
3+
 
,AlMg)
 
2-3
((Si,Al)
 
2
O
 
5
)(OH)
 
4
9.ED.15Brindleyite
(Ni,Mg,Fe)
 
2
(Al(Si,Al)O
 
5
)(OH)
 
4
9.ED.15Caryopilite
(Mn,Mg)
 
3
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.15Chrysotile
Mg
 
3
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.15Cronstedtite
Fe
2+
2
Fe
3+
 
((Si,Fe
3+
 
)
 
2
O
 
5
)(OH)
 
4
9.ED.15Fraipontite
(Zn,Al)
 
3
((Si,Al)
 
2
O
 
5
)(OH)
 
4
9.ED.15Greenalite
Fe
 
2-3
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.15Kellyite
Mn
2+
2
Al(AlSiO
 
5
)(OH)
 
4
9.ED.15Lizardite
Mg
 
3
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.15Manandonite
LiAl
 
4
(BSi
 
3
O
 
10
)(OH)
 
6
9.ED.15Népouite
(Ni,Mg)
 
3
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.15Pecoraite
Ni
 
3
(Si
 
2
O
 
5
)(OH)
 
4
9.ED.15Guidottiite
Mn
 
2
Fe
3+
 
(Fe
3+
 
SiO
 
5
)(OH)
 
4
9.ED.20Allophane
(Al
 
2
O
 
3
)(SiO
 
2
)
 
1.3-2
 · 2.5-3H
 
2
O
9.ED.20Chrysocolla
Cu
 
2-x
Al
 
x
(H
 
2-x
Si
 
2
O
 
5
)(OH)
 
4
 · nH
 
2
O (x < 1)
9.ED.20Imogolite
Al
 
2
SiO
 
3
(OH)
 
4
9.ED.20Neotocite
(Mn,Fe,Mg)SiO
 
3
 · H
 
2
O
9.ED.25Bismutoferrite
Fe
3+
2
Bi(SiO
 
4
)
 
2
(OH)
9.ED.25Chapmanite
Fe
3+
2
Sb
3+
 
(SiO
 
4
)
 
2
(OH)

Other Names for Halloysite-7Å

Synonyms:
Dehydrated halloysiteMetahalloysite
Other Languages:
Simplified Chinese:变叙永石

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 Halloysite-7Å

Reference List:

- +
Berthier (1826)

American Mineralogist 39 (1954), 97

American Mineralogist 40 (1955), 1110

Acta Crystallographica B31 (1975), 2851

Clays and Clay Minerals 26 (1978), 25

Powder Diffraction 4 (1989), 19

Clays and Clay Minerals (1991): 39: 113.

Handbook of Mineralogy (Anthony et al.), 2 (1995), 311




Internet Links for Halloysite-7Å

Search Engines:
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  • Look for Halloysite-7Å on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
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  • Mineral Classics - Worldwide Collector Quality Minerals and Gems
  • Find Halloysite-7Å on www.crystalclassics.co.uk
  • Edwards Minerals - Fine Specimens
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  • Pricedownminerals.com - Reverse Auctions and Shop
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    • Localities for Halloysite-7Å

    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.
    Hide Locality List
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Belgium
     
    • Liège Province
      • Liège
    		Ann.Chim.Phys., sér. 2 (1826) 32, 332-335
    China
     
    • Fujian Province
      • Xiamen Prefecture
        • Tong'an District
    		Mao Xingli and Yan Yipeng (1987): Journal of Fuzhou University, Natural Sciences Edition 15(3); Acta Petrologica et Mineralogica 11(2), 146-156 (1992)
    • Guangxi Zhuang Autonomous Region
      • Baise Prefecture
        • Pingguo Co.
    		Zhongcao Liang (1983): Geology and Prospecting 19(8), 24-28; Xinyu Cao and Tongjiang Tang (1986): Geology and Prospecting 22(2), 18-23
    • Hunan Province
      • Huaihua Prefecture
        • Chenxi Co.
    		Shu-Gen Zhang, Xiao-Hu Liu, and Jun Ding (2006): Acta Petrologica et Mineralogica [Yanshikuangwuxue Zazhi] 25(5), 433-439.
    Germany
     
    • Rhineland-Palatinate
      • Eifel
        • Laach lake volcanic complex
          • Mendig
            • Niedermendig
    		Blass, G.; Graf, H.W., Neue Mineralienfunde aus der Eifel und dem Siegerland, Mineralien-Welt 10/3, 23, 1999
    Blass, G.; Graf, H.W., Neue Mineralienfunde aus der Eifel und dem Siegerland, Mineralien-Welt 10/3, 23, 1999
      • Siegerland
        • Gebhardshain
          • Kausen
    		Wittern: "Mineralfundstellen in Deutschland", 2001
    Indonesia
     
    • Jawa Island (Java Island)
      • Jawa Barat Province (West Java Province)
        • Bogor District
    		Milési, J.P., Marcoux, E., Sitorus, T., Simandjuntak, M., Leroy, J., and Bailly, L. (1999): Mineralium Deposita 34, 131-149.
    Peru
     
    • Cajamarca Department
      • Cajamarca Province
        • Cajamarca
    		Dill, H.G., Bosse, H.-R., Henning, K.-H., Fricke, A., and Ahrendt, H. (1997): Mineralium Deposita 32, 149-163.
    Russia
     
    • Urals Region
      • Southern Urals
        • Orenburgskaya Oblast'
          • Dombarov District
    		Gorbachev, B.F., Sharapov, A.F., Lyadskii, P.V., and Shmel'kov, N.T. (2004): The South Ushkoty Eluvial Kaolin Deposit in the Southeastern Orenburg Region. Lithology and Mineral Resources 39(5), 412-424.
          • Svetlyi
            • Buruktal District
              • Buruktal massif
    		Talovina, I.V., Lazarenkov, V.G., and Vorontsova, N.I. (2003): Lithology and Mineral Resources 38(5), 403-415.
    USA
     
    • Maine
      • Oxford Co.
        • Paris
    		King, V. T. and Foord, E. E., 1994, Mineralogy of Maine, Descriptive Mineralogy, volume 1, Maine Geological Survey, Augusta, Maine, USA, pp. 418 + 88 plates.
    • North Carolina
      • Catawba Co.
    		Bates,Thomas F.,Hiderbrand,Fred A.,and Swineford,Ada.,(1950) Morphology and Structure of Endellite and Halloysite: The American Mineralogist,Vol.35,July-August,1950,No.7-8
    Bates,Thomas F.,Hiderbrand,Fred A.,and Swineford,Ada.,(1950) Morphology and Structure of Endellite and Halloysite :The American Mineralogist ,Vol.35.July-August,1950,No.7-8
      • Jackson Co.
    		Bates,Thomas F.,Hiderbrand,Fred A.,and Swineford,Ada (1950) Morphology and Structure of Endellite and Halloysite : The American Mineralogist,Vol.35,July-Aug,1950,No.7-8
      • Macon Co.
        • Cowee Valley
          • Ellijay District
            • Franklin
    		Clays and Clay Minerals,39 and 113, 1991
      • Mitchell Co.
        • Spruce Pine District
          • Spruce Pine
    		Johnson,Sheryl L.,Guggenheim,Stephen and Van Groos,A.F Koster (1990)Thermal Stability of Halloysite by High-Pressure Differential Thermal Analysis :Clay and Clay Minerals,Vol.38,No.5,pg.477-484,1990
    Mineral and/or Locality
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    Copyright © Jolyon Ralph and Ida Chau 1993-2012. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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