Portlandite Mineral Data

General Portlandite Information

Chemical Formula:

Ca(OH)2

Composition:

Molecular Weight = 74.09 gm

Calcium 54.09 % Ca 75.69 % CaO

Hydrogen 2.72 % H 24.31 % H₂O

Oxygen 43.19 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca(OH)₂

Environment:

Larnite-spurrite contact rocks and volcanic fumaroles.

IMA Status:

Valid Species (Pre-IMA) 1933

Locality:

Scawt Hill, Antrim County, Northern Ireland. Link to MinDat.org Location Data.

Name Origin:

Named because the material is a common product of hydration of portland cement.

Name Pronunciation:

Portlandite + Pronunciation

Synonym:

ICSD 15471

PDF 44-1481

Portlandite Image

Images:

Portlandite

Comments: Cleaved mass of white portlandite.
Location: Wessels Mine, Kalahari Manganese Field, Northern Cape Province, South Africa. Scale: 4 x 1.5 cm.
© John Veevaert

Portlandite Crystallography

Axial Ratios:

a:c = 1:1.36541

Cell Dimensions:

a = 3.585, c = 4.895, Z = 1; V = 54.48 Den(Calc)= 2.26

Crystal System:

Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: P 3m1

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

By Intensity(I/I_o): 2.628(1), 4.9(0.74), 1.927(0.42),

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Forms: ( 1 0 0) ( 0 0 1)

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Crystal Structure:

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Henderson D M , Gutowsky H S , American Mineralogist , 47 (1962) p.1231-1251, A nuclear magnetic resonance determination of the hydrogen positions in Ca(OH)2, T = -190 C

View Additional jPOWD Structure files for Portlandite
[1] [2] [3] [4] [5] [6] [7] [8]

Physical Properties of Portlandite

Cleavage:

{0001} Perfect

Color:

Colorless.

Density:

2.23

Diaphaneity:

Transparent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Hexagonal - Six-sided crystal shape in cross-section or habit.

Habit:

Platy - Sheet forms (e.g. micas).

Hardness:

2.5-3 - Finger Nail-Calcite

Luster:

Pearly

Streak:

white

Optical Properties of Portlandite

Gladstone-Dale:

CI meas= -0.04 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.026 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.248,KPDmeas= 0.2513,KC= 0.2416
Ncalc = 1.54 - 1.55

Optical Data:

Uniaxial (-), e=1.547, w=1.574, bire=0.0270.

Calculated Properties of Portlandite

Electron Density:

Bulk Density (Electron Density)=2.32 gm/cc
note: Specific Gravity of Portlandite =2.26 gm/cc.

Fermion Index:

Fermion Index = 0.0009416194
Boson Index = 0.9990583806

Photoelectric:

PE_Portlandite= 6.54 barns/electron
U=PE_Portlandite x rElectron Density= 15.16 barns/cc.

Radioactivity:

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

Portlandite Classification

Dana Class:

06.02.01.04 (06)Hydroxides and Oxides Containing Hydroxyl

(06.02)where X++ (OH)2

(06.02.01)Brucite group (Rhombohedral: P-3m1)

06.02.01.01 Brucite Mg(OH)2 P 3m1 3 2/m

06.02.01.02 Amakinite (Fe,Mg)(OH)2 P 3m1 3 2/m

06.02.01.03 Pyrochroite Mn(OH)2 P 3m1 3 2/m

06.02.01.04 Portlandite Ca(OH)2 P 3m1 3 2/m

06.02.01.05 Theophrastite Ni(OH)2 P 3m1 3 2/m

Strunz Class:

04.FE.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.F - Hydroxides (without V or U)

04.FE -Hydroxides with OH, without H2O; sheets of edge-sharing octahedra

04.FE.05 Amakinite (Fe,Mg)(OH)2 P 3m1 3 2/m

04.FE.05 Brucite Mg(OH)2 P 3m1 3 2/m

04.FE.05 Portlandite Ca(OH)2 P 3m1 3 2/m

04.FE.05 Pyrochroite Mn(OH)2 P 3m1 3 2/m

04.FE.05 Theophrastite Ni(OH)2 P 3m1 3 2/m

04.FE.05 Fougerite! (Fe,Mg)6Fe2(OH)18•4(H2O) R 3m 3 2/m

Other Portlandite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Portlandite :
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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Ask about Portlandite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Portlandite

Ca(OH)2
Dana No: 06.02.01.04 Strunz No: 04.FE.05
Locality:

Notes: