Akermanite Mineral Data

General Akermanite Information

Chemical Formula:

Ca2MgSi2O7

Composition:

Molecular Weight = 272.63 gm

Calcium 29.40 % Ca 41.14 % CaO

Magnesium 8.92 % Mg 14.78 % MgO

Silicon 20.60 % Si 44.08 % SiO₂

Oxygen 41.08 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂Mg(Si₂O₇)

Environment:

A product of contact metamorphism of siliceous limestones and dolostones, and in rocks of the sanidinite facies. Also, forms from alkalic magmas rich in calcium.

IMA Status:

Valid Species (Pre-IMA) 1884

Locality:

Occurrences are typically of intermediate series members; relatively pure examples have been found at Monte Somma and Vesuvius, Campania, and Monte Cavalluchio, Sacrofano, near Rome, L Link to MinDat.org Location Data.

Name Origin:

For Anders Richard Akerman (1837-1922), Swedish metallurgist.

Name Pronunciation:

Akermanite + Pronunciation

Synonym:

ICSD 39924

PDF 35-592

Akermanite Image

Images:

Akermanite

Comments: White translucent crystals akermanite.
Location: Lago de Vico, Viterbo, Lazio, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Akermanite Crystallography

Axial Ratios:

a:c = 1:0.63903

Cell Dimensions:

a = 7.84, c = 5.01, Z = 2; V = 307.94 Den(Calc)= 2.94

Crystal System:

Tetragonal - ScalenohedralH-M Symbol (4 2m) Space Group: P 42₁m

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

By Intensity(I/I_o): 2.87(1), 1.76(0.3), 3.09(0.3),

Crystal Structure:

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Swainson I P , Dove M T , Schmahl W W , Putnis A , Physics and Chemistry of Minerals , 19 (1992) p.185-195, Neutron powder diffraction study of the akermanite-gehlenite, solid solution series, Sample: 50% Ak

View Additional jPOWD Structure files for Akermanite
[1] [10] [11] [12] [13] [14] [15] [16] [17] [18] [2] [3] [4] [5] [6] [7] [8] [9]

Physical Properties of Akermanite

Cleavage:

{001} Distinct, {110} Indistinct

Color:

Colorless, Grayish, Green, Brown.

Density:

2.944

Diaphaneity:

Transparent to Translucent

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Vitreous - Resinous

Streak:

white

Optical Properties of Akermanite

Gladstone-Dale:

CI meas= -0.04 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.042 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2163,KPDmeas= 0.216,KC= 0.2076
Ncalc = 1.61

Optical Data:

Uniaxial (+), w=1.632, e=1.64, bire=0.0080.

Calculated Properties of Akermanite

Electron Density:

Bulk Density (Electron Density)=2.94 gm/cc
note: Specific Gravity of Akermanite =2.94 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Akermanite= 4.59 barns/electron
U=PE_Akermanite x rElectron Density= 13.48 barns/cc.

Radioactivity:

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

Akermanite Classification

Dana Class:

55.04.01.01 (55)Sorosilicate Si2O7 Groups, Generally with No Additional Anions

(55.04)with cations in [8] and lower coordination

(55.04.01)Melilite group

55.04.01.01 Akermanite Ca2MgSi2O7 P 42₁m 4 2m

55.04.01.02 Gehlenite Ca2Al(AlSi)O7 P 42₁m 4 2m

55.04.01.03 Melilite (Ca,Na)2(Al,Mg,Fe)(Si,Al)2O7 P 42₁m 4 2m

55.04.01.04 Okayamalite! Ca2B2SiO7 P 42₁m 4 2m

55.04.01.05 Alumoakermanite! (Ca,Na)2(Al,Mg,Fe)(Si2O7) P 42₁m 4 2m

Strunz Class:

09.BB.10 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BB -Si2O7 groups, without non-tetrahedral anions;

09.BB.10 Akermanite Ca2MgSi2O7 P 42₁m 4 2m

09.BB.10 Cebollite Ca5Al2(SiO4)3(OH)4 Unk Ortho

09.BB.10 Gugiaite Ca2BeSi2O7 P 42₁m 4 2m

09.BB.10 Gehlenite Ca2Al(AlSi)O7 P 42₁m 4 2m

09.BB.10 Jeffreyite (Ca,Na)2(Be,Al)Si2(O,OH)7 C 222₁ 2 2 2

09.BB.10 Hardystonite Ca2ZnSi2O7 P 42₁m 4 2m

09.BB.10 Melilite (Ca,Na)2(Al,Mg,Fe)(Si,Al)2O7 P 42₁m 4 2m

09.BB.10 Okayamalite! Ca2B2SiO7 P 42₁m 4 2m

Other Akermanite 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 Akermanite :
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 - University of Colorado - Mineral Structure Data
16 - WWW-MINCRYST

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

Akermanite

Ca2MgSi2O7
Dana No: 55.04.01.01 Strunz No: 09.BB.10
Locality:

Notes: