Tobermorite Mineral Data
General Tobermorite Information
Chemical Formula:
Ca5Si6O16(OH)2•4(H2O)
Composition:
Molecular Weight = 702.36 gm
Calcium 24.54 % Ca 34.33 % CaO
Aluminum 1.92 % Al 3.63 % Al2 O3
Silicon 21.99 % Si 47.05 % SiO2
Hydrogen 1.44 % H 12.82 % H2 O
Oxygen 50.11 % O
______ ______
100.00 % 97.84 % = TOTAL OXIDE
Empirical Formula:
Ca4.3 Si5.5 Al0.5 O16 (OH)2 •4(H2 O)
Environment:
A hydrothermal alteration product of calcium carbonate rocks, due to contact metamorphism and metasomatism. Filling vesicles and cavities in basaltic rocks.
IMA Status:
Valid Species (Pre-IMA) 1880
Locality:
In Scotland, on the Isle of Mull, around Tobermory. Link to MinDat.org Location Data.
Name Origin:
Named for the locality.
Name Pronunciation:
Tobermorite + Pronunciation
Synonym:
Crestmoreite - mixture with wilkeite
Tobermorite Image
Images:
Tobermorite Crystallography
Axial Ratios:
a:b:c =1.5416:1:3.0832
Cell Dimensions:
a = 11.3, b = 7.33, c = 22.6, Z = 4; V = 1,871.94 Den(Calc)= 2.49
Crystal System:
Orthorhombic - Disphenoidal H-M Symbol (2 2 2) Space Group: C 2221
X Ray Diffraction:
By Intensity(I/Io ): 14(1), 3.706(0.65), 3.001(0.45), 1.835(0.35), 2.812(0.3), 5.5(0.25), 2.793(0.13),
Physical Properties of Tobermorite
Cleavage:
{001} Perfect, {100} Imperfect
Color:
White, Light pink white, Reddish white.
Density:
2.423 - 2.44, Average = 2.43
Diaphaneity:
Translucent
Habit:
Aggregates - Made of numerous individual crystals or clusters.
Habit:
Fibrous - Crystals made up of fibers.
Habit:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Hardness:
2.5 - Finger Nail
Luminescence:
Fluorescent, Short UV=weak white to yellow, Long UV=weak white to yellow.
Luster:
Silky
Streak:
white
Optical Properties of Tobermorite
Gladstone-Dale:
CI meas = -0.064 (Fair) - where the CI = (1-KPDmeas /KC ) CI calc = -0.039 (Good) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2297,KPDmeas = 0.2352,KC = 0.2211 Ncalc = 1.54 - 1.55
Optical Data:
Biaxial (+), a=1.57, b=1.571, g=1.575, bire=0.0050
Pleochroism (x):
colorless.
Pleochroism (y):
colorless.
Pleochroism (z):
colorless.
Calculated Properties of Tobermorite
Electron Density:
Bulk Density (Electron Density)=2.52 gm/cc note: Specific Gravity of Tobermorite =2.49 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PETobermorite = 3.91 barns/electronU=PETobermorite x r Electron Density= 9.86 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Tobermorite is Not Radioactive
Tobermorite Classification
Dana Class:
72.03.02.01 (72) Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
(72.03) with 3-, 4-, or 5-membered rings and 8-membered rings
(72.03.02) Tobermorite group (5- & 8-membered rings)
72.03.02.01 Tobermorite Ca5Si6O16(OH)2•4(H2O) C 2221 2 2 2
72.03.02.02 Clinotobermorite Ca5Si6(O,OH)18•5(H2O) Cc,C 2/c Mono
72.03.02.03 Plombierite Ca5H2Si6O18•6H2O B11b 2
72.03.02.04 Riversideite Ca5Si6O16(OH)2•2(H2O) B2212 2 2 2
72.03.02.05 Okenite Ca3[Si6O15]•6(H2O) P1 or P1 Tri
72.03.02.06 Tacharanite Ca12Al2Si18O33(OH)36 A centered Mono
72.03.02.07 Nekoite Ca3Si6O15•7(H2O) P1 1
72.03.02.08 Oyelite Ca10B2Si8O29•12(H2O) B**** Ortho
Strunz Class:
09.DG.10 09 - SILICATES (Germanates)
09.D - Inosilicates* Structural terminology according to Liebau (1985)
09.DG -Inosilicates with 3-periodic single and multiple chains
09.DG.10 Clinotobermorite Ca5Si6(O,OH)18•5(H2O) Cc,C 2/c Mono
09.DG.10 Riversideite Ca5Si6O16(OH)2•2(H2O) B2212 2 2 2
09.DG.10 Tobermorite Ca5Si6O16(OH)2•4(H2O) C 2221 2 2 2
Other Tobermorite Information
References:
NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
See Also:
Links to other databases for Tobermorite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST
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Tobermorite
Ca5Si6O16(OH)2•4(H2O)
Dana No: 72.03.02.01 Strunz No: 09.DG.10
Locality:
Notes:
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