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Åkermanite

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Ettringer Bellerberg Mt., Ettringen, Mayen, Eifel Mts, Rhineland-Palatinate, Germany
© Stephan Wolfsried

Show Åkermanite Photos (3)
Formula:
Ca
 
2
Mg[Si
 
2
O
 
7
]
System:TetragonalColour:grey-green, brown, ...
Hardness:5 - 6
Name:Named after Anders Richard Åkerman, Swedish metallurgist.


Gehlenite-Åkermanite Series.

Classification of Åkermanite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/C.02-10
Nickel-Strunz 10th (pending) edition ID:9.BB.10

9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
Dana 8th edition ID:55.4.1.1

55 : SOROSILICATES Si2O7 Groups,Generally with no Additional Anions
4 : Si2O7 Groups, Generally with No Additional Anions with cations in [8] and lower coordination
Hey's CIM Ref.:14.6.9

14 : Silicates not Containing Aluminum
6 : Silicates of Ca with alkali or Mg or both
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Physical Properties of Åkermanite

Lustre:Vitreous, Resinous
Colour:grey-green, brown, colourless
Streak:white
Hardness (Mohs):5 - 6
Cleavage:Distinct/Good

Crystallography of Åkermanite

Crystal System:Tetragonal

Optical Data of Åkermanite

Type:Uniaxial (+)
RI values: nω = 1.632 nε = 1.640
Maximum Birefringence:δ = 0.008

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

Chemical Properties of Åkermanite

Formula:
Ca
 
2
Mg[Si
 
2
O
 
7
]
Essential elements:Ca, Mg, O, Si
All elements listed in formula:Ca, Mg, O, Si

Relationship of Åkermanite to other Species

Series:Forms a series with Gehlenite (see here)
Related to:
  • Melilite
    • Related Minerals - Nickel-Strunz Grouping):
    9.BB.10Cebollite
    Ca
     
    5
    		Al
     
    2
    		Si
     
    3
    		O
     
    12
    		(OH)
     
    4
    		 or near
    9.BB.10Gehlenite
    Ca
     
    2
    		Al[AlSiO
     
    7
    		]
    9.BB.10Gugiaite
    Ca
     
    2
    		Be[Si
     
    2
    		O
     
    7
    		]
    9.BB.10Hardystonite
    Ca
     
    2
    		Zn[Si
     
    2
    		O
     
    7
    		]
    9.BB.10Jeffreyite
    (Ca,Na)
     
    2
    		(Be,Al)[Si
     
    2
    		O
     
    6
    		(O,OH)]
    9.BB.10Okayamalite
    Ca
     
    2
    		B[BSiO
     
    7
    		]
    9.BB.15Barylite
    BaBe
     
    2
    		[Si
     
    2
    		O
     
    7
    		]
    9.BB.15Clinobarylite
    BaBe
     
    2
    		Si
     
    2
    		O
     
    7
    9.BB.20Andrémeyerite
    BaFe
    2+
    2
    		[Si
     
    2
    		O
     
    7
    		]
    Related Minerals - Hey's Index Grouping:
    14.6.1Combeite
    Na
     
    2
    		Ca
     
    2
    		Si
     
    3
    		O
     
    9
    14.6.2Pectolite
    NaCa
     
    2
    		[HSi
     
    3
    		O
     
    9
    		]
    14.6.3Pectolite-M2abc
    NaCa
     
    2
    		[HSi
     
    3
    		O
     
    9
    		]
    14.6.4Denisovite
    Ca
     
    2
    		(K,Na)Si
     
    3
    		O
     
    8
    		(F,OH)
     
    2
    14.6.5Tokkoite
    K
     
    2
    		Ca
     
    4
    		Si
     
    7
    		O
     
    17
    		(O,OH,F)
     
    4
    14.6.6Mountainite
    (Ca,Na
     
    2
    		,K
     
    2
    		)
     
    2
    		[Si
     
    4
    		O
     
    10
    		] · 3H
     
    2
    		O
    14.6.7Rhodesite
    KHCa
     
    2
    		Si
     
    8
    		O
     
    19
    		·5H
     
    2
    		O
    14.6.8Miserite
    K(Ca,Ce)
     
    4
    		Si
     
    5
    		O
     
    13
    		(OH)
     
    3
    14.6.10Monticellite
    CaMg[SiO
     
    4
    		]
    14.6.11Merwinite
    Ca
     
    3
    		Mg[SiO
     
    4
    		]
     
    2
    14.6.12Diopside
    CaMg[Si
     
    2
    		O
     
    6
    		]
    14.6.13Tremolite
    ☐[Ca
     
    2
    		][Mg
     
    5
    		][(OH)
     
    2
    		|Si
     
    8
    		O
     
    22
    		]

    Other Names for Åkermanite

    Synonyms:
    OakermaniteOkermanite
    German names:
    ÅkermanitOakermanitOkermanit
    Russian names:
    Окерманит
    Spanish names:
    ÅkermanitaOakermanitaOkermanita
    Varieties:
    Justite (of Hofmann-Degen)

    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 Åkermanite

    Reference List:Christie, O.H.J. (1961) On sub-solidus relations of silicates; IV. The system åkermanite-sodium-gehlenite and gehlenite-sodium-gehlenite. Norsk Geologisk Tidsskrift: 42: 31-44.

    Valley, J.W. and Essene, E.J. (1979) Vesuvianite, akermanite, monticellite and wollastonite equlibria and high X H2O/CO2 at Cascade slide, Mt Marcy Quad, Adirondack Mts. EOS: 60: 423.

    Neues Jahrbuch für Mineralogie, Monatshefte (1981): 1-10.

    Courtial, P., Téqui, C., and Richet, P. (2000) Thermodynamics of diopside, anorthite, pseudowollastonite, CaMgGeO4 olivine, and åkermanite up to near the melting point. Physics and Chemistry of Minerals: 27: 242-250.

    Internet Links for Åkermanite

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  • Look for Åkermanite on Wikipedia
  • Look for Åkermanite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Åkermanite in the Natural History Museum (London) online catalogue
  • Åkermanite details from Handbook of Mineralogy (PDF)
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  • Search for Åkermanite at Thames Valley Minerals
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    Localities for Åkermanite

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    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.
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    (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.
    Canada
     
    • Newfoundland and Labrador
      • Labrador
    		Am Min 85:1595–1605, (2000)
    • Québec
      • Deux-Montagnes Co.
        • Oka complex
          • Oka
    		Sabina (1968)
          • St-Joseph-du-Lac
    		Sabina (1968)
    Czech Republic
     
    • Bohemia (Böhmen; Boehmen)
      • Ústí Region
        • Duchcov (Dux)
    		Žáček V., Skála R., Chlupáčová M., Dvořák Z. 2005: Ca-Fe3+-rich, Si-undersaturated buchite from Želénky, North-Bohemian Brown Coal Basin, Czech Republic. Eur. J. Mineral., 17, 623-633
    Germany
     
    • Lower Saxony
      • Harz Mts
        • Goslar
          • Astfeld
    		No reference listed
    • Rhineland-Palatinate
      • Eifel Mts
        • Mayen
          • Ettringen
    		[Blass, G., Graf, H.W., Neue Mineralienfunde aus der Eifel und dem Siegerland, Mineralien-Welt 10/3, 23, 1999] [A. Wittern: Mineralfundorte in Deutschland, Schweizerbart (Stuttgart), 2001]
    Iraq
     
    • Qala-Diz (Qala-Dizeh; Qala-Diza)
      • Hero
    Israel
     
    Gross, S. (1977): The Mineralogy of the Hatrurim Formation, Israel. Geological Survey of Israel, Bulletin no. 70, 80 pp.
    Italy
     
    • Campania
      • Naples Province
        • Somma-Vesuvius Complex
    		[Lapis 1994:5 p.13-23,58]
    • Latium
      • Rome Province
        • Campagnano di Roma
          • Sacrofano
            • Sacrofano Caldera
    Japan
     
    • Honshu Island
      • Chugoku region
        • Shimane Prefecture
    		The Mineral Species of Japan (5th ed) Matsubara
    Norway
     
    • Telemark
      • Skien
    		Jamtveit B., Dahlgren S. and Austrheim H., (1997): "High-grade contact metamorphism of calcareous rocks from the Oslo Rift, Southern Norway".
    Russia
     
    • Northern Region
      • Murmanskaja Oblast'
        • Kola Peninsula
    		www.koeln.netsurf.de/~w.steffens/khib.htm
    South Africa
     
    • Mpumalanga Province
      • Eastern Bushveld Complex
        • Lydenburg District
    		Minerals of South Africa
    • Northern Cape Province
      • Kalahari manganese fields
        • Hotazel
    		[Von Bezing, K. L. et al. (1991) - The Kalahari manganese field : an update, Mineralogical Record, 22 (3), 279-302]
    Sweden
     
    • Medelpad
      • Sundsvall
    		No reference listed
    UK
     
    • Scotland
      • North West Highlands (Argyllshire)
        • Ardnamurchan
    		Handbook of Mineralogy - Anthony, Bideaux, Bladh, Nichols
    USA
     
    • Colorado
      • Gunnison Co.
        • White Earth District (Powderhorn District)
    		"Minerals of Colorado, updated & revised", p. 17, by Eckel, Edwin B., 1997
    • New York
      • Essex Co.
        • Keene
          • Cascade Mountain
    		EOS: 60: 423.
    • Texas
      • Culberson Co.
        • Apache Peak area
    		Rocks & Minerals: 66(3): 196-224.
    Mineral and/or Locality
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