Leightonite Mineral Data

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General Leightonite Information

Chemical Formula:

K2Ca2Cu(SO4)4•2(H2O)

Composition:

Molecular Weight = 705.73 gm

Potassium 11.08 % K 13.35 % K₂O

Calcium 11.36 % Ca 15.89 % CaO

Copper 18.01 % Cu 22.54 % CuO

Hydrogen 0.57 % H 5.11 % H₂O

Sulfur 18.17 % S 45.38 % SO₃

Oxygen 40.81 % O

______ ______

100.00 % 102.27 % = TOTAL OXIDE

Empirical Formula:

K₂Ca₂Cu₂(SO₄)₄•2(H₂O)

Environment:

Arid environments in oxidized copper sulfide ore deposits with low acidity. Structurally related to polyhalite.

IMA Status:

Valid Species (Pre-IMA) 1938

Locality:

Chuquicamata, Antofagasta, Chile. Link to MinDat.org Location Data.

Name Origin:

Named for T. Leighton, mineralogist at the University of Sanitago, Chile.

Name Pronunciation:

Leightonite + Pronunciation

Leightonite Image

Images:

Leightonite

Comments: Pale Leightonite with dark green atacamite.
Location: Chuquicamata, Antofagasta, Chile. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Leightonite Crystallography

Axial Ratios:

a:b:c =1.5544:1:1.3468

Cell Dimensions:

a = 11.654, b = 7.497, c = 10.097, Z = 2; beta = 125.21° V = 720.78 Den(Calc)= 3.25

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/c

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

By Intensity(I/I_o): 2.9(1), 3.18(0.6), 1.781(0.3),

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Forms: ( 0 3 1) ( 1 3 0) ( 0 1 0) ( 1 3 1) ( 1 0 1) ( 1 1 0)

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Crystal Structure:

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Menchetti S , Bindi L , Bonazzi P , Olmi F , American Mineralogist , 87 (2002) p.721-725, Disordered distribution of Cu in the crystal structure of leightonite,, K2Ca2Cu(SO4)4.2H2O

Physical Properties of Leightonite

Cleavage:

None

Color:

Blue green, Light blue.

Density:

2.95

Diaphaneity:

Transparent to Translucent

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

3 - Calcite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Leightonite

Gladstone-Dale:

CI meas= -0.017 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.077 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1805,KPDmeas= 0.1989,KC= 0.1955
Ncalc = 1.58 - 1.64

Optical Data:

Biaxial (-), a=1.578, b=1.587, g=1.595, bire=0.0170, 2V(Calc)=86, 2V(Meas)=86.15.

Calculated Properties of Leightonite

Electron Density:

Bulk Density (Electron Density)=2.91 gm/cc
note: Specific Gravity of Leightonite =2.95 gm/cc.

Fermion Index:

Fermion Index = 0.0017264599
Boson Index = 0.9982735401

Photoelectric:

PE_Leightonite= 11.32 barns/electron
U=PE_Leightonite x r_electron= 32.95 barns/cc.

Radioactivity:

GRapi = 157.65 (Gamma Ray American Petroleum Institute Units)
Concentration of Leightonite per GRapi unit = 0.63 (%)

Estimated Radioactivity from Leightonite - barely detectable

Leightonite Classification

Dana Class:

29.04.05.02 (29)Hydrated Acid and Sulfates

(29.04)where (A+)2 Bn (XO4)p · x(H2O)

(29.04.05)Dana Group

29.04.05.01 Polyhalite K2Ca2Mg(SO4)4•2(H2O) P 1,P1 Tri

29.04.05.02 Leightonite K2Ca2Cu(SO4)4•2(H2O) C 2/c 2/m

Strunz Class:

07.CC.70 07 - SULFATES (SELENATES, TELLURATES)

07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O

07.CC -With medium-sized and large cations

07.CC.70 Leightonite K2Ca2Cu(SO4)4•2(H2O) C 2/c 2/m

Other Leightonite Information

References:

NAME( AmMin, Vol 87, p 721) PHYS. PROP.(AmMin, Vol 87, p 721) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Leightonite :
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 Leightonite Specimen Label here :

Leightonite

K2Ca2Cu(SO4)4•2(H2O)
Dana No: 29.04.05.02 Strunz No: 07.CC.70
Locality:

Notes: