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Laumontite

Formula:
CaAl
 
2
Si
 
4
O
 
12
·4H
 
2
O
System:MonoclinicColour:Colorless to Pink, ...
Hardness:3½ - 4
Name:Named Laumonite by Huäy in 1808 honoring Gillet de Laumont (1747-1834). Changed to Laumontite in 1821.


Zeolite Group. Laumontite Subgroup.

Normally it dehydrates in air to form a white powder. Specimens should be kept moist to prevent decomposition.

Classification of Laumontite

IMA status:Approved 1805
Strunz 8th edition ID:8/J.22-50
Nickel-Strunz 10th (pending) edition ID:9.GB.10

9 : SILICATES (Germanates)
G : Tektosilicates with zeolitic H2O; zeolite family
B : Chains of single connected 4-membered rings
Dana 8th edition ID:77.1.1.4

77 : TECTOSILICATES Zeolites
1 : Zeolite group - True zeolites
Hey's CIM Ref.:16.9.23

16 : Silicates Containing Aluminum and other Metals
9 : Aluminosilicates of Ca
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Type Occurrence of Laumontite

Type Locality:Huelgoat, Finistère, Brittany, France
Year of Discovery:1805

Occurrences of Laumontite

Geological Setting:Hydrothermal origin, decomposition of analcime, sandstone cement.

Physical Properties of Laumontite

Lustre:Vitreous, Pearly
Diaphaneity (Transparency):Transparent, Translucent
Comment:Pearly on cleavage
Colour:Colorless to Pink, white, gray, yellowish, brownish, golden brown
Streak:White
Hardness (Mohs):3½ - 4
Tenacity:Brittle
Cleavage:Perfect
on {010}{110}
Fracture:Irregular/Uneven
Density (measured):2.23 - 2.41 g/cm3
Density (calculated):2.25 g/cm3

Crystallography of Laumontite

Crystal System:Monoclinic
Class (H-M):2/m - Prismatic
Space Group:B2/m (B1 1 2/m) [C2/m] {C1 2/m 1}
Cell Parameters:a = 14.724(9) Å, b = 13.075(6) Å, c = 7.559(2) Å
β = 112.01(3)°
Ratio:a:b:c = 1.126 : 1 : 0.578
Unit Cell Volume:V 1,349.17 ų (Calculated from Unit Cell)
Z:4
Morphology:Square prisms with steep oblique terminations, radiating, columnar, fibrous, massive
Twinning:On {100}
Crystal Atlas:
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Laumontite no.49 - Goldschmidt (1913-1926)

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X-Ray Powder Diffraction:
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Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data: Peaks:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Laumontite

Type:Biaxial (-)
RI values: nα = 1.502 - 1.514 nβ = 1.512 - 1.522 nγ = 1.514 - 1.525
2V:Measured: 26° to 47°, Calculated: 34° to 44°
Maximum Birefringence:δ = 0.012

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

Chemical Properties of Laumontite

Formula:
CaAl
 
2
Si
 
4
O
 
12
·4H
 
2
O
Essential elements:Al, Ca, H, O, Si
All elements listed in formula:Al, Ca, H, O, Si
Common Impurities:Na,K,Fe

Relationship of Laumontite to other Species

Related to:
  • Laumontite Subgroup
  • Related Minerals - Nickel-Strunz Grouping):
    9.GB.05Ammonioleucite
    (NH
     
    4
    ,K)AlSi
     
    2
    O
     
    6
    9.GB.05Analcime
    Na
     
    2
    [Al
     
    2
    Si
     
    4
    O
     
    12
    ] · 2H
     
    2
    O
    9.GB.05Hsianghualite
    Ca
     
    3
    Li
     
    2
    Be
     
    3
    [F
     
    2
    |(SiO
     
    4
    )
     
    3
    ]
    9.GB.05Lithosite
    K
     
    6
    Al
     
    4
    Si
     
    8
    O
     
    25
    ·2H
     
    2
    O
    9.GB.05Leucite
    KAlSi
     
    2
    O
     
    6
    9.GB.05Pollucite
    (Cs,Na)
     
    2
    [Al
     
    2
    Si
     
    4
    O
     
    12
    ] · 2H
     
    2
    O
    9.GB.05Wairakite
    Ca[Al
     
    2
    Si
     
    4
    O
     
    12
    ] · 2H
     
    2
    O
    9.GB.15Yugawaralite
    CaAl
     
    2
    Si
     
    6
    O
     
    16
    ·4H
     
    2
    O
    9.GB.20Roggianite
    Ca
     
    2
    Be(OH)
     
    2
    Al
     
    2
    Si
     
    4
    O
     
    13
    ·2.5H
     
    2
    O
    9.GB.25Goosecreekite
    Ca[Al
     
    2
    Si
     
    6
    O
     
    16
    ] · 5H
     
    2
    O
    9.GB.30Montesommaite
    (K,Na)
     
    9
    Al
     
    9
    Si
     
    23
    O
     
    64
    ·10H
     
    2
    O
    9.GB.35Parthéite
    CaAl
     
    2
    Si
     
    2
    O
     
    8
    ·2H
     
    2
    O
    Related Minerals - Hey's Index Grouping:
    16.9.1Gehlenite
    Ca
     
    2
    Al[AlSiO
     
    7
    ]
    16.9.2Anorthite
    Ca[Al
     
    2
    Si
     
    2
    O
     
    8
    ]
    16.9.3Yoshiokaite
    (Ca,Na)[Al(Al,Si)O
     
    4
    ]
    16.9.4Svyatoslavite
    Ca[Al
     
    2
    Si
     
    2
    O
     
    8
    ]
    16.9.5Dmisteinbergite
    Ca[Al
     
    2
    Si
     
    2
    O
     
    8
    ]
    16.9.6Grossular
    Ca
     
    3
    Al
     
    2
    [SiO
     
    4
    ]
     
    3
    16.9.7Vuagnatite
    CaAl[OH|SiO
     
    4
    ]
    16.9.8Zoisite
    {Ca
     
    2
    }{Al
     
    3
    }[O|OH|SiO
     
    4
    |Si
     
    2
    O
     
    7
    ]
    16.9.9Clinozoisite
    {Ca
     
    2
    }{Al
     
    3
    }[O|OH|SiO
     
    4
    |Si
     
    2
    O
     
    7
    ]
    16.9.10Prehnite
    Ca
     
    2
    Al
     
    2
    Si
     
    3
    O
     
    12
    (OH)
    16.9.11Kamaishilite
    Ca
     
    2
    [(OH)
     
    2
    |Al
     
    2
    SiO
     
    6
    ]
    16.9.12Bicchulite
    Ca
     
    2
    [(OH)
     
    2
    |Al
     
    2
    SiO
     
    6
    ]
    16.9.13Margarite
    CaAl
     
    2
    [(OH)
     
    2
    |Al
     
    2
    Si
     
    2
    O
     
    10
    ]
    16.9.14Chantalite
    CaAl
     
    2
    [(OH)
     
    4
    |SiO
     
    4
    ]
    16.9.15Cebollite
    Ca
     
    5
    Al
     
    2
    Si
     
    3
    O
     
    12
    (OH)
     
    4
    or near
    16.9.17Katoite
    Ca
     
    3
    Al
     
    2
    [(OH)
     
    8-6
    |(SiO
     
    4
    )
     
    1-1.5
    ]
    16.9.18Lawsonite
    CaAl
     
    2
    [(OH)
     
    2
    |Si
     
    2
    O
     
    7
    ] · 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
    Ca[Al
     
    2
    Si
     
    3
    O
     
    10
    ] · 3H
     
    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 Laumontite

    Synonyms:
    LeonharditeSchneiderite
    German names:
    ÄdelforsitLaumontit
    Russian names:
    Ломонтит
    Spanish names:
    Laumontita
    Varieties:
    Vanadio-laumontite

    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 Laumontite

    Reference List:Madsen, B.M. & K.J. Murata (1970), Occurrence of Laumontite in the Tertiary sandstones of the central Coast Ranges of California USGS PP 700-D: 188-195.

    Neues Jahrbuch für Mineralogie, Monatshefte (1970): 298-310.

    Thompson, A.B. (1970) Laumontite equilibria and the zeolite facies. American Journal of Science: 269: 267-275.

    Journal of Petrology (1971): 12: 379.

    Neues Jahrbuch für Mineralogie, Monatshefte (1992): 385.

    Zeolites (1993): 13: 249.

    European Journal of Mineralogy (1993): 5: 851.

    Physics and Chemistry of Minerals (1996): 23: 328.

    Canadian Mineralogist (1997): 35: 1571.

    Reviews in Mineralogy and Geochemistry (2001): 45: 1.

    Reviews in Mineralogy and Geochemistry (2001): 45: 69.

    Reviews in Mineralogy and Geochemistry (2001): 45: 117.

    American Mineralogist (2003): 88 (2003), 277.

    Lee, Y., J.A. Hriljac, & T. Vogt (2004a), Pressure-induced migration of zeolitic water in laumontite: Physics and Chemistry of Minerals: 31: 421-428.

    Internet Links for Laumontite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Laumontite in the Natural History Museum (London) online catalogue
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    Localities for Laumontite

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