Guanacoite Mineral Data

General Guanacoite Information

Chemical Formula:

(Cu,Mg)2Mg2(Mg,Cu)(OH)4(H2O)4(AsO4)2

Composition:

Molecular Weight = 612.83 gm

Magnesium 12.41 % Mg 20.59 % MgO

Copper 19.39 % Cu 24.27 % CuO

Arsenic 24.45 % As 37.50 % As₂O₅

Hydrogen 1.97 % H 17.64 % H₂O

Oxygen 41.77 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

2(Cu_0.85)2(Mg_0.15)Mg₂Mg_0.83Cu_0.17(OH)₄(AsO₄)₂(H₂O)₄

Environment:

Isotypic with akrochordite

IMA Status:

Approved IMA 2003 (Dana # Added)

Locality:

Mine dump at the El Guanaco Mine, East Catalina, Chile, South America Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Synonym:

IMA2003-021

Guanacoite Image

Images:

Guanacoite

Comments: Deep blue, bladed, glassy crystals of guanacoite to 0.75mm lining vugs of arhbarite..
Location: El Guanaco Mine, Guanaco, Taltal, Antofagasta Province, Chile. Scale: Picture Size 5mm.
© Tom Loomis / Dakota Matrix

Guanacoite Crystallography

Axial Ratios:

a:b:c =0.3247:1:0.4115

Cell Dimensions:

a = 5.459, b = 16.808, c = 6.917, Z = 2; beta = 100.44° V = 624.16 Den(Calc)= 3.26

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 8.42(1), 4.21(0.64), 4.32(0.21),3.016(0.12), 2.907(0.1), 2.809(0.07),

Physical Properties of Guanacoite

Color:

Blue, Pale blue.

Diaphaneity:

Transparent

Habit:

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

Luster:

Vitreous (Glassy)

Streak:

pale blue

Optical Properties of Guanacoite

Gladstone-Dale:

CI calc= -0.032 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2096,KC= 0.2032
Ncalc = 1.66

Optical Data:

Biaxial (-), a=1.664, b=1.691, g=1.695, bire=0.0310

Calculated Properties of Guanacoite

Electron Density:

Bulk Density (Electron Density)=3.17 gm/cc
note: Specific Gravity of Guanacoite =3.26 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Guanacoite= 25.03 barns/electron
U=PE_Guanacoite x rElectron Density= 79.31 barns/cc.

Radioactivity:

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

Guanacoite Classification

Dana Class:

42.04.01.02 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.04)where (AB)5 (XO4)2 Zq ï¿½ x(H2O)

(42.04.01)Akrochordite Group

42.04.01.01 Akrochordite Mn4Mg(AsO4)2(OH)4•4(H2O) P 2₁/c 2/m

42.04.01.02 Guanacoite! (Cu,Mg)2Mg2(Mg,Cu)(OH)4(H2O)4(AsO4)2 P 2₁/c 2/m

Strunz Class:

08.DD.10 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DD -With only medium-sized cations, (OH, etc.):RO4 = 2:1

08.DD.10 Akrochordite Mn4Mg(AsO4)2(OH)4•4(H2O) P 2₁/c 2/m

08.DD.10 Guanacoite! (Cu,Mg)2Mg2(Mg,Cu)(OH)4(H2O)4(AsO4)2 P 2₁/c 2/m

Other Guanacoite Information

References:

NAME( AmMin, v93:501) PHYS. PROP.(AmMin, v93:501) OPTIC PROP.(AmMin, v93:501)

See Also:

Links to other databases for Guanacoite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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

Guanacoite

(Cu,Mg)2Mg2(Mg,Cu)(OH)4(H2O)4(AsO4)2
Dana No: 42.04.01.02 Strunz No: 08.DD.10
Locality:

Notes:

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