Gatumbaite Mineral Data

General Gatumbaite Information

Chemical Formula:

CaAl2(PO4)2(OH)2•(H2O)

Composition:

Molecular Weight = 336.01 gm

Calcium 11.93 % Ca 16.69 % CaO

Aluminum 16.06 % Al 30.34 % Al₂O₃

Phosphorus 18.44 % P 42.24 % P₂O₅

Hydrogen 1.20 % H 10.72 % H₂O

Oxygen 52.38 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaAl₂(PO₄)₂(OH)₂•(H₂O)

IMA Status:

Approved IMA 1977

Locality:

Buranga pegmatite, near Gatumba, Gisenyi Province, Rwanda. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Gatumbaite + Pronunciation

Gatumbaite Image

Images:

Gatumbaite Apatite-(CaF)

Comments: White crystalline gatumbaite with yellow brazilianite in massive blue fluorapatite.
Location: Buranga Pegmatite, near Gatumba, Gisenyi, Rwanda. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Burangaite Gatumbaite

Comments: Small, blue burangaite crystals in beige gatumbaite.
Location: Horrsjoberg, Torby, VÃ¤rmland, Sweden. Scale: Micro-mount Size.
© Sonke Stolze / Systematic Minerals

Gatumbaite Crystallography

Axial Ratios:

a:b:c =1.3556:1:2.1126

Cell Dimensions:

a = 6.907, b = 5.095, c = 10.764, Z = 2; beta = 91.05° V = 378.73 Den(Calc)= 2.95

Crystal System:

Monoclinic Space Group: P12/m,P 2,Pm

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

By Intensity(I/I_o): 2.241(1), 4.21(1), 1.726(0.75),

Physical Properties of Gatumbaite

Cleavage:

{???} Good, {???} Good

Color:

White.

Density:

2.92

Diaphaneity:

Translucent

Fracture:

Brittle - Splintery - Brittle fracture leaving splintery fragments.

Habit:

Rosette - Bundled tabular aggregates resembling rose flower petals.

Habit:

Scaly - Morphology like fish scales.

Habit:

Wheat Sheaf - Bundle shaped aggregates resembling wheat sheafs after hand reaping wheat.

Hardness:

4-5 - Fluorite-Apatite

Luminescence:

Non-fluorescent.

Luster:

Pearly

Streak:

white

Optical Properties of Gatumbaite

Gladstone-Dale:

CI meas= -0.014 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.003 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2123,KPDmeas= 0.2145,KC= 0.2116
Ncalc = 1.62

Optical Data:

Biaxial (-), a=1.61, b=1.63, g=1.639, bire=0.0290, 2V(Calc)=66, 2V(Meas)=65.

Calculated Properties of Gatumbaite

Electron Density:

Bulk Density (Electron Density)=2.95 gm/cc
note: Specific Gravity of Gatumbaite =2.95 gm/cc.

Fermion Index:

Fermion Index = 0.0004142297
Boson Index = 0.9995857703

Photoelectric:

PE_Gatumbaite= 2.83 barns/electron
U=PE_Gatumbaite x rElectron Density= 8.35 barns/cc.

Radioactivity:

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

Gatumbaite Classification

Dana Class:

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

(42.11)where (AB)4 (XO4)3 Zq ï¿½ x(H2O)

(42.11.12)Gatumbaite Group

42.11.12.01 Gatumbaite CaAl2(PO4)2(OH)2•(H2O) P12/m,P 2,Pm Mono

42.11.12.02 Kleemanite ZnAl2(PO4)2(OH)2•3(H2O) P 2, P 2₁, P 2/m or P 2₁/m Mono

Strunz Class:

08.DJ.10 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

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

08.DJ.10 Gatumbaite CaAl2(PO4)2(OH)2•(H2O) P12/m,P 2,Pm Mono

Other Gatumbaite Information

References:

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

See Also:

Links to other databases for Gatumbaite :
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

Search for Gatumbaite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Gatumbaite :

Ask about Gatumbaite 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 Gatumbaite Specimen Label here :

Gatumbaite

CaAl2(PO4)2(OH)2•(H2O)
Dana No: 42.11.12.01 Strunz No: 08.DJ.10
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.