Gaitite Mineral Data

General Gaitite Information

Chemical Formula:

Ca2Zn(AsO4)2•2(H2O)

Composition:

Molecular Weight = 459.41 gm

Calcium 17.45 % Ca 24.41 % CaO

Zinc 14.23 % Zn 17.72 % ZnO

Arsenic 32.62 % As 50.03 % As₂O₅

Hydrogen 0.88 % H 7.84 % H₂O

Oxygen 34.83 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂Zn(AsO₄)₂•2(H₂O)

Environment:

Secondary arsenate mineral.

IMA Status:

Approved IMA 1980

Locality:

Tsumeb mine, Tsumeb, Namibia. Link to MinDat.org Location Data.

Name Origin:

Named for Rober Irwin Gait (1938-), curator of mineralogy, Royal Ontario Museum, Toronto, Canada.

Name Pronunciation:

Gaitite

Synonym:

IMA1978-047

Gaitite Image

Images:

Gaitite

Comments: Opaque white spherical gaitite with transparent crystalline calcite.
Location: Twin Creeks Mine, Humboldt County, Nevada, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Gaitite Crystallography

Axial Ratios:

a:b:c =0.8453:1:0.8247

Cell Dimensions:

a = 5.899, b = 6.978, c = 5.755, Z = 1; alpha = 94.41°, beta = 109.08°, gamma = 108.09° V = 212.18 Den(Calc)= 3.60

Crystal System:

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

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

By Intensity(I/I_o): 2.781(1), 3.08(0.8), 2.75(0.7),

Crystal Structure:

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Keller P , Lissner F , Schleid T , European Journal of Mineralogy , 16 (2004) p.353-359, The crystal structures of zincroselite and gaitite: Two natural, polymorphs of Ca2Zn[AsO4]2·2H2O from Tsumeb, Namibia, Note: c cell edge corrected by authors, Locality: Tsumeb, Namibia

Physical Properties of Gaitite

Cleavage:

{010} Good, {001} Good, {011} Good

Color:

Colorless, White.

Density:

3.81

Diaphaneity:

Transparent

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

5 - Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Gaitite

Gladstone-Dale:

CI meas= -0.025 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.067 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1995,KPDmeas= 0.1917,KC= 0.187
Ncalc = 1.68 - 1.71

Optical Data:

Biaxial (+), a=1.713, b=1.73, g=1.748, bire=0.0350, 2V(Calc)=90, 2V(Meas)=88.

Calculated Properties of Gaitite

Electron Density:

Bulk Density (Electron Density)=3.65 gm/cc
note: Specific Gravity of Gaitite =3.81 gm/cc.

Fermion Index:

Fermion Index = 0.0062396803
Boson Index = 0.9937603197

Photoelectric:

PE_Gaitite= 31.40 barns/electron
U=PE_Gaitite x rElectron Density= 114.59 barns/cc.

Radioactivity:

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

Gaitite Classification

Dana Class:

40.02.02.06 (40)Hydrated Phosphates, etc

(40.02)where A++ (B++)2 (XO4) · x(H2O)

(40.02.02)Fairfieldite Subgroup (Triclinic: P-1¯)

40.02.02.01 Fairfieldite Ca2(Mn,Fe)(PO4)2•2(H2O) P1 1

40.02.02.02 Messelite Ca2(Fe,Mn)(PO4)2•2(H2O) P1 1

40.02.02.03 Collinsite Ca2(Mg,Fe)(PO4)2•2(H2O) P1 1

40.02.02.04 Cassidyite Ca2(Ni,Mg)(PO4)2•2(H2O) P1 1

40.02.02.05 Talmessite Ca2Mg(AsO4)2•2(H2O) P1 1

40.02.02.06 Gaitite Ca2Zn(AsO4)2•2(H2O) P1 1

40.02.02.07 Roselite-beta Ca2(Co,Mg)(AsO4)2•2(H2O) P 1 or P1 Tri

40.02.02.08 Parabrandtite Ca2Mn(AsO4)•2(H2O) P1,P 1 Tri

40.02.02.09 Hillite! Ca2(Zn,Mg)[PO4]2•2(H2O) P1 1

40.02.02.10 Nickeltalmessite! Ca2Ni(AsO4)2•2H2O P 1

Strunz Class:

08.CG.05 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CG -With large and medium-sized cations, RO4:H2O = 1:1

08.CG.05 Collinsite Ca2(Mg,Fe)(PO4)2•2(H2O) P1 1

08.CG.05 Gaitite Ca2Zn(AsO4)2•2(H2O) P1 1

08.CG.05 Cassidyite Ca2(Ni,Mg)(PO4)2•2(H2O) P1 1

08.CG.05 Fairfieldite Ca2(Mn,Fe)(PO4)2•2(H2O) P1 1

08.CG.05 Messelite Ca2(Fe,Mn)(PO4)2•2(H2O) P1 1

08.CG.05 Parabrandtite Ca2Mn(AsO4)•2(H2O) P1,P 1 Tri

08.CG.05 Uranophane-beta Ca[(UO2)SiO3(OH)]2•(H2O) P 2₁/a 2/m

08.CG.05 Talmessite Ca2Mg(AsO4)2•2(H2O) P1 1

08.CG.05 Hillite! Ca2(Zn,Mg)[PO4]2•2(H2O) P1 1

Other Gaitite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990, AmMin 90:522) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Gaitite :
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

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

Gaitite

Ca2Zn(AsO4)2•2(H2O)
Dana No: 40.02.02.06 Strunz No: 08.CG.05
Locality:

Notes: