Angastonite Mineral Data

General Angastonite Information

Chemical Formula:

CaMgAl2(PO4)2(OH)4?7H2O

Composition:

Molecular Weight = 502.43 gm

Calcium 7.98 % Ca 11.16 % CaO

Magnesium 4.84 % Mg 8.02 % MgO

Aluminum 10.74 % Al 20.29 % Al₂O₃

Phosphorus 12.33 % P 28.25 % P₂O₅

Hydrogen 3.61 % H 32.27 % H₂O

Oxygen 60.50 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaMgAl₂(PO₄)₂(OH)₄•7(H₂O)

Environment:

Penrice marble quarry. Related to the montgomeryite-group.

IMA Status:

Approved IMA 2008 (Dana # Added)

Locality:

Angaston, in the Mount Lofty Ranges, 100 km NNE of Adelaide, South Australia, Australia. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Synonym:

IMA2008-008

Angastonite Image

Images:

Angastonite

Comments: SEM image of platy, striated crystals of angastonite.
Location: Angaston, South Australia. Scale: Unknown.
© Mineralogical Magazine

Images:

Angastonite

Comments: White acicular to short prismatic crystals of angastonite covering a dark matrix.
Location: Penrice quarry, Angaston, South Australia, Australia. Scale: Overall: 5.5 x 3.5 x 2 cm.
© Tom Loomis / Dakota Matrix

Angastonite Crystallography

Axial Ratios:

a:b:c =0.4923:1:0.226

Cell Dimensions:

a = 13.303, b = 27.02, c = 6.107, Z = 6; alpha = 89.64°, beta = 83.44°, gamma = 80.444° V = 2,150.47 Den(Calc)= 2.33

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 13.38(1), 11.05(0.25), 5.73(0.23),8.01(0.21),

Physical Properties of Angastonite

Cleavage:

{010} Distinct

Color:

White.

Density:

2.47

Diaphaneity:

Transparent

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

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

Hardness:

2 - Gypsum

Luster:

Pearly

Streak:

white

Optical Properties of Angastonite

Gladstone-Dale:

CI meas= 0.043 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.014 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2464,KPDmeas= 0.2324,KC= 0.2429
Ncalc = 1.57 - 1.6

Optical Data:

Biaxial (+), a=1.566, b=1.572, g=1.584, bire=0.0180, 2V(Calc)=72, 2V(Meas)=70. Dispersion dispersion not observed.

Calculated Properties of Angastonite

Electron Density:

Bulk Density (Electron Density)=2.39 gm/cc
note: Specific Gravity of Angastonite =2.33 gm/cc.

Fermion Index:

Fermion Index = 0.0052410621
Boson Index = 0.9947589379

Photoelectric:

PE_Angastonite= 2.04 barns/electron
U=PE_Angastonite x rElectron Density= 4.89 barns/cc.

Radioactivity:

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

Angastonite Classification

Dana Class:

42.11.08.05 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq · x(H2O)

(42.11.08)Montgomeryite group

42.11.08.01 Montgomeryite Ca4MgAl4(PO4)6(OH)4•12(H2O) C 2/c 2/m

42.11.08.02 Kingsmountite (Ca,Mn)4(Fe,Mn)Al4(PO4)6(OH)4•12(H2O) C 2 2

42.11.08.03 Calcioferrite Ca4Fe(Fe,Al)4(PO4)6(OH)4•12(H2O) C 2 2

42.11.08.04 Zodacite Ca4MnFe4(PO4)6(OH)4•12(H2O) C 2/c,Cc Mono

42.11.08.05 Angastonite! CaMgAl2(PO4)2(OH)4?7H2O P1 1

Strunz Class:

08.DL.25 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DL -With large and medium-sized cations, (OH, etc.):RO4 = 2:1

08.DL.25 Angastonite! CaMgAl2(PO4)2(OH)4?7H2O P1 1

Other Angastonite Information

References:

NAME( MinMag, v72:1011) PHYS. PROP.(MinMag, v72:1011) OPTIC PROP.(MinMag, v72:1011)

See Also:

Links to other databases for Angastonite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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

Angastonite

CaMgAl2(PO4)2(OH)4?7H2O
Dana No: 42.11.08.05 Strunz No: 08.DL.25
Locality:

Notes: