Gaitite Mineral Data

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.

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

Diaphaniety:

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= -0.085 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2029,KPDmeas= 0.1917,KC= 0.187

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:

r_electron=3.65 gm/cc
note: r_Gaitite=3.81 gm/cc.

Fermion Index

Fermion Index = 0.00623
Boson Index = 0.99377

Photoelectric:

PE_Gaitite= 31.40 barns/electron
U=PE_Gaitite x r_electron= 114.59 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Gaitite is Not Radioactive

Gaitite Classification

Dana Class:

40.2.2.6 (40)Hydrated Phosphates, etc

(40.2)where A++ (B++)2 (XO4) · x(H2O)

(40.2.2)Fairfieldite Subgroup (Triclinic: P1¯)

40.2.2.1 Fairfieldite Ca2(Mn,Fe)(PO4)2·2(H2O) P1 1

40.2.2.2 Messelite Ca2(Fe,Mn)(PO4)2·2(H2O) P1 1

40.2.2.3 Collinsite Ca2(Mg,Fe)(PO4)2·2(H2O) P1 1

40.2.2.4 Cassidyite Ca2(Ni,Mg)(PO4)2·2(H2O) P1 1

40.2.2.5 Talmessite Ca2Mg(AsO4)2·2(H2O) P1 1

40.2.2.6 Gaitite Ca2Zn(AsO4)2·2(H2O) P1 1

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

40.2.2.8 Parabrandtite Ca2Mn(AsO4)·2(H2O) P1,P 1 Tri

40.2.2.9 Hillite! Ca2(Zn,Mg)[PO4]2·2(H2O) P1 1

Strunz Class:

VII/C.17-60 VII - Phosphates, Arsenates and Vanadates

VII/C - Water-bearing phosphates without unfamiliar anions, cations of medium and big size: Fe, Mn, Zn, Mg and Ca, (NH4)1+

VII/C.17 - Collinsite - Wendwilsonite series

VII/C.17-10 Collinsite Ca2(Mg,Fe)(PO4)2·2(H2O) P1 1

VII/C.17-15 Hillite! Ca2(Zn,Mg)[PO4]2·2(H2O) P1 1

VII/C.17-20 Messelite Ca2(Fe,Mn)(PO4)2·2(H2O) P1 1

VII/C.17-30 Fairfieldite Ca2(Mn,Fe)(PO4)2·2(H2O) P1 1

VII/C.17-40 Cassidyite Ca2(Ni,Mg)(PO4)2·2(H2O) P1 1

VII/C.17-50 Talmessite Ca2Mg(AsO4)2·2(H2O) P1 1

VII/C.17-60 Gaitite Ca2Zn(AsO4)2·2(H2O) P1 1

VII/C.17-70 Parabrandtite Ca2Mn(AsO4)·2(H2O) P1,P 1 Tri

VII/C.17-80 Roselite-beta Ca2(Co,Mg)(AsO4)2·2(H2O) P 1 or P1 Tri

VII/C.17-90 Wendwilsonite Ca2(Mg,Co)(AsO4)2·2(H2O) P 2₁/c 2/m

VII/C.17-100 Roselite Ca2(Co,Mg)(AsO4)2·2(H2O) P 2₁/c 2/m

VII/C.17-110 Brandtite Ca2(Mn,Mg)(AsO4)2·2(H2O) P 2₁/c 2/m

VII/C.17-120 Zincroselite Ca2Zn(AsO4)2·2(H2O) P 2₁/c 2/m

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 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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Gaitite

Ca2Zn(AsO4)2·2(H2O)
Dana No: 40.2.2.6 Strunz No: VII/C.17-60
Locality:

Notes: