Laumontite Mineral Data

General Laumontite Information

Chemical Formula:

CaAl2Si4O12•4(H2O)

Composition:

Molecular Weight = 470.44 gm

Calcium 8.52 % Ca 11.92 % CaO

Aluminum 11.47 % Al 21.67 % Al₂O₃

Silicon 23.88 % Si 51.09 % SiO₂

Hydrogen 1.71 % H 15.32 % H₂O

Oxygen 54.42 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaAl₂Si₄O₁₂•4(H₂O)

Environment:

Secondary mineral in basalts and andesites. Also occurs in metamorphic rocks and granites. Found in copper veins.

IMA Status:

Valid Species (Pre-IMA) 1801

Locality:

Nagy-Ag, Transylvania of Romania. Link to MinDat.org Location Data.

Name Origin:

Named after the Frenchman, F. P. N. de Laumont (1747-1834).

Name Pronunciation:

Laumontite + Pronunciation

Synonym:

Aedelforsite

Caporcianite

ICSD 72914

Leonhardite

Lomonite

PDF 45-1325

Laumontite Image

Images:

Laumontite

Comments: Diamond-shaped prism of laumontite with chrysocolla.
Location: Azurite mine, Pinal County, Arizona, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Images:

Laumontite

Comments: White, well developed laumontite crystals up to 1 cm. on matrix.
Location: Osilo, Sardegna, Italy. Scale: Specimen size 6 x 4.5 cm.
© Sandro Maggia/Minernet.it

Laumontite Crystallography

Axial Ratios:

a:b:c =1.1313:1:0.5732

Cell Dimensions:

a = 14.9, b = 13.17, c = 7.55, Z = 4; beta = 111.5° V = 1,378.47 Den(Calc)= 2.27

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 9.49(1), 4.156(0.6), 6.86(0.35),

Crystal Structure:

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Fridriksson T , Bish D L , Bird D K , American Mineralogist , 88 (2003) p.277-287, Hydrogen-bonded water in laumontite I: X-ray powder diffraction, study of water site occupancy and structural changes in laumontite, during room-temperature isothermal hydration/dehydration, Sample: P = 0.11 mbar PH2O

View Additional jPOWD Structure files for Laumontite
[1] [10] [11] [12] [13] [14] [15] [2] [3] [4] [5] [6] [7] [8] [9]

Physical Properties of Laumontite

Cleavage:

{010} Perfect, {110} Perfect

Color:

Brownish, Gray, Yellowish, Pearl white, Pink.

Density:

2.25 - 2.35, Average = 2.29

Diaphaneity:

Transparent to translucent to opaque

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Bladed - Aggregates of thin lath-like crystals (e.g. kyanite).

Habit:

Crystalline - Fine - Occurs as well-formed fine sized crystals.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

3.5-4 - Copper Penny-Fluorite

Luminescence:

Fluorescent, Short UV=Weak white, Long UV=weak white.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Laumontite

Gladstone-Dale:

CI meas= 0.017 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.004 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2274,KPDmeas= 0.2244,KC= 0.2282
Ncalc = 1.51 - 1.54

Optical Data:

Biaxial (-), a=1.502-1.519, b=1.512-1.525, g=1.513-1.526, bire=0.0070-0.0110, 2V(Calc)=34-44, 2V(Meas)=25-47. Dispersion marked to extreme, r < v.

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Calculated Properties of Laumontite

Electron Density:

Bulk Density (Electron Density)=2.30 gm/cc
note: Specific Gravity of Laumontite =2.27 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Laumontite= 2.32 barns/electron
U=PE_Laumontite x rElectron Density= 5.33 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Laumontite is Not Radioactive

Laumontite Classification

Dana Class:

77.01.01.04 (77)Tectosilicate Zeolite group

(77.01)true zeolites

(77.01.01)Analcime and related species

77.01.01.01 Analcime NaAlSi2O6•(H2O) P1 1

77.01.01.02 Pollucite (Cs,Na)2Al2Si4O12•(H2O) I a3d 4/m 3 2/m

77.01.01.03 Wairakite CaAl2Si4O12•2(H2O) I2/a 2/m

77.01.01.04 Laumontite CaAl2Si4O12•4(H2O) C 2/m 2/m

77.01.01.05 Hsianghualite Ca3Li2Be3(SiO4)3F2 I 2₁3 2 3

Strunz Class:

09.GB.10 09 - SILICATES (Germanates)

09.G - Tektosilicates with Zeolitic H2O

09.GB -Chains of single connected 4-membered rings

09.GB.10 Laumontite CaAl2Si4O12•4(H2O) C 2/m 2/m

Other Laumontite Information

See Also:

Links to other databases for Laumontite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - Franklin Minerals(Dunn)
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - Philatelic Mineralogy
16 - QUT Mineral Atlas
17 - Ruff.Info
18 - WWW-MINCRYST
19 - Zeolite Database by Bruno Herreros

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Ask about Laumontite here :
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Mindat.org's Discussion Groups
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Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Laumontite Specimen Label here :

Laumontite

CaAl2Si4O12•4(H2O)
Dana No: 77.01.01.04 Strunz No: 09.GB.10
Locality:

Notes: