Atacamite Mineral Data

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General Atacamite Information

Chemical Formula:

Cu2Cl(OH)3

Composition:

Molecular Weight = 213.57 gm

Copper 59.51 % Cu 74.49 % CuO

Hydrogen 1.42 % H 12.65 % H₂O

Chlorine 16.60 % Cl 16.60 % Cl

- % Cl -3.75 % -O=Cl₂

Oxygen 22.47 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Cu₂Cl(OH)₃

Environment:

Arid climates with oxidizable copper minerals.

IMA Status:

Valid Species (Pre-IMA) 1801

Locality:

Atacam desert province in northern Chile. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Name Pronunciation:

Atacamite + Pronunciation

Synonym:

ICSD 61252

PDF 25-269

Paratacamite

Atacamite Image

Images:

Atacamite

Comments: Atacamite in a well crystallized pocket.
Location: Mina Lily, Pisco Umay, Ica Dept. Peru. Scale: 5 x 4.5 cm.
© Fabre Minerals

Images:

Atacamite Santarosaite

Comments: Encrustations of santarosaite (Cotype Specimen, MD212; blue) with atacamite (green) and anhydrite (white) on matrix. Discovered by Arturo Molina, Iquique, Chile in 2003. Holotype, sample MD 87, largely used up for the examinations.
Location: Santa Rosa Mine, Iquique, Chile. Scale: Sample Width 3 cm.
© K.C. Lyncker, Hamburg / German Type Specimen Catalogue

Atacamite Crystallography

Axial Ratios:

a:b:c =0.7491:1:0.6582

Cell Dimensions:

a = 6.84, b = 9.13, c = 6.01, Z = 4; V = 375.32 Den(Calc)= 3.78

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pmcn

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

By Intensity(I/I_o): 2.82(1), 5(1), 5.4(1),

Forms:

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

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Crystal Structure:

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Wells A F , Acta Crystallographica , 2 (1949) p.175-180, The crystal structure of atacamite and the crystal chemistry of, cupric compounds

View Additional jPOWD Structure files for Atacamite
[1]

Physical Properties of Atacamite

Cleavage:

{010} Perfect

Color:

Green, Yellow, Yellow green, Black green.

Density:

3.76 - 3.78, Average = 3.76

Diaphaneity:

Transparent to translucent

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Habit:

Fibrous - Crystals made up of fibers.

Habit:

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

Hardness:

3-3.5 - Calcite-Copper Penny

Luminescence:

Non-fluorescent.

Luster:

Adamantine

Streak:

apple green

Optical Properties of Atacamite

Gladstone-Dale:

CI meas= -0.024 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.021 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2268,KPDmeas= 0.2274,KC= 0.2221
Ncalc = 1.84

Optical Data:

Biaxial (-), a=1.831, b=1.861, g=1.88, bire=0.0490, 2V(Calc)=74, 2V(Meas)=75. Dispersion strong, r < v.

Calculated Properties of Atacamite

Electron Density:

Bulk Density (Electron Density)=3.61 gm/cc
note: Specific Gravity of Atacamite =3.78 gm/cc.

Fermion Index:

Fermion Index = 0.0001100017
Boson Index = 0.9998899983

Photoelectric:

PE_Atacamite= 27.37 barns/electron
U=PE_Atacamite x rElectron Density= 98.83 barns/cc.

Radioactivity:

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

Atacamite Classification

Dana Class:

10.01.01.01 (10)Oxyhalides and Hydroxyhalides

(10.01)where (A)2 (O,OH)3 Xq

(10.01.01)Atacamite group

10.01.01.01 Atacamite Cu2Cl(OH)3 Pmcn 2/m 2/m 2/m

10.01.01.02 Hibbingite (Fe,Mg)2(OH)3Cl Pnam 2/m 2/m 2/m

10.01.01.03 Gillardite! Cu3NiCl2(OH)6 R 3m 3

10.01.01.04 Haydeeite! Cu3Mg(OH)6Cl2 R 3m 3

Strunz Class:

03.DA.10a 03 - HALIDES

03.D - Oxyhalides, Hydroxyhalides and Related Double Halides

03.DA -With Cu, etc., without Pb

03.DA.10a Atacamite Cu2Cl(OH)3 Pmcn 2/m 2/m 2/m

03.DA.10a Hibbingite (Fe,Mg)2(OH)3Cl Pnam 2/m 2/m 2/m

03.DA.10a Kempite Mn2Cl(OH)3 Pnam 2/m 2/m 2/m

Other Atacamite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

See Also:

Links to other databases for Atacamite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - Franklin Minerals(Dunn)
7 - GeoScienceWorld
8 - Glendale Community College
9 - Google Images
10 - Google Scholar
11 - Handbook of Mineralogy (MinSocAm)
12 - Handbook of Mineralogy (UofA)
13 - MinDAT
14 - Mineralienatlas (Deutsch)
15 - Online Mineral Museum
16 - Philatelic Mineralogy
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - WWW-MINCRYST
20 - YupRocks
21 - theimage

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

Atacamite

Cu2Cl(OH)3
Dana No: 10.01.01.01 Strunz No: 03.DA.10a
Locality:

Notes: