Koktaite Mineral Data

Koktaite Mineral Data +

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General Koktaite Information

Chemical Formula:

(NH4)2Ca(SO4)2·(H2O)

Composition:

Molecular Weight = 286.30 gm

Calcium 14.00 % Ca 19.59 % CaO

Hydrogen 2.82 % H - % Calc as (NH₄)₂O

Hydrogen 0.70 % H 6.29 % H₂O

Sulfur 22.40 % S 55.93 % SO₃

Nitrogen 9.78 % N 18.19 % (NH₄)₂O

Oxygen 50.30 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

(NH₄)₂Ca(SO₄)₂·(H₂O)

Environment:

Waste heaps of a lignite mine. Pseudomorphous after gypsum.

IMA Status:

Valid Species (Pre-IMA) 1948

Locality:

Zeravice, near Kyjov in southeastern Moravia, Czech Republic. Link to MinDat.org Location Data.

Name Origin:

Named for Jaroslav Kokta (1904-1970), Czech chemist, who analyzed the artificial compound.

Koktaite Image

Images:

Koktaite

Comments: Tan to white scaly coating of koktaite.
Location: Zastavka, near Brna, Vychodocesky, Czech Republic. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Koktaite Crystallography

Axial Ratios:

a:b:c =0.887:1:1.4164

Cell Dimensions:

a = 6.324, b = 7.129, c = 10.098, Z = 2; beta = 102.58° V = 444.33 Den(Calc)= 2.14

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/m

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

By Intensity(I/I_o): 9.83(1), 3.3(0.65), 4.96(0.4),

Physical Properties of Koktaite

Cleavage:

None

Color:

Colorless, White.

Density:

2.09

Diaphaniety:

Transparent

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Water Soluble - Water soluble mineral.

Streak:

white

Optical Properties of Koktaite

Gladstone-Dale:

CI meas= -0.572 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.535 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.248,KPDmeas= 0.2539,KC= 0.1615

Optical Data:

Biaxial (-), a=1.524, b=1.532, g=1.536, bire=0.0120, 2V(Calc)=70, 2V(Meas)=72.

Calculated Properties of Koktaite

Electron Density:

r_electron=2.21 gm/cc
note: r_Koktaite=2.14 gm/cc.

Fermion Index

Fermion Index = 0.0996
Boson Index = 0.9004

Photoelectric:

PE_Koktaite= 3.04 barns/electron
U=PE_Koktaite x r_electron= 6.73 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Koktaite is Not Radioactive

Koktaite Classification

Dana Class:

29.3.1.2 (29)Hydrated Acid and Sulfates

(29.3)where (A+)2 B (XO4)2 · x(H2O)

(29.3.1)Dana Group

29.3.1.1 Syngenite K2Ca(SO4)2·(H2O) P 2₁/m 2/m

29.3.1.2 Koktaite (NH4)2Ca(SO4)2·(H2O) P 2₁/m 2/m

Strunz Class:

VI/C.21-70 VI - Sulfates,Chromates,Molybdates and Tungstates

VI/C - Water-bearing sulfates without unfamiliar anions. Cations of very big size

VI/C.21 - Matteuccite - Mirabilite series

VI/C.21-10 Matteuccite NaHSO4·(H2O) Aa m

VI/C.21-20 Lecontite (NH4,K)Na(SO4)·2(H2O) P 2₁2₁2₁ 2 2 2

VI/C.21-30 Eugsterite Na4Ca(SO4)3·2(H2O) Unk. Mono

VI/C.21-40 Hydroglauberite Na4Ca(SO4)3·2(H2O) Unk. Ortho

VI/C.21-50 Wattevillite Na2Ca(SO4)2·4(H2O)(?) Unk Ortho

VI/C.21-60 Syngenite K2Ca(SO4)2·(H2O) P 2₁/m 2/m

VI/C.21-70 Koktaite (NH4)2Ca(SO4)2·(H2O) P 2₁/m 2/m

VI/C.21-80 Mirabilite Na2SO4·10(H2O) P 2₁/a 2/m

Other Koktaite Information

References:

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

See Also:

Links to other databases for Koktaite :
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 - WWW-MINCRYST 13 -École des Mines de Paris

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

Koktaite

(NH4)2Ca(SO4)2·(H2O)
Dana No: 29.3.1.2 Strunz No: VI/C.21-70
Locality:

Notes: