Esperanzaite Mineral Data

General Esperanzaite Information

Chemical Formula:

NaCa2Al2(As+++++O4)2F4(OH)•2(H2O)

Composition:

Molecular Weight = 563.98 gm

Sodium 4.08 % Na 5.49 % Na₂O

Calcium 14.21 % Ca 19.89 % CaO

Aluminum 9.57 % Al 18.08 % Al₂O₃

Arsenic 26.57 % As 40.75 % As₂O₅

Hydrogen 0.89 % H 7.99 % H₂O

Oxygen 31.21 % O

Fluorine 13.47 % F 13.47 % F

- % F -5.67 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

NaCa₂Al₂(AsO₄)₂F₄(OH)•2(H₂O)

Environment:

Found as a secondary phase on mineralized rhyolite.

IMA Status:

Approved IMA 1999 (Dana # Added)

Locality:

La Esperanza mine, Zaragosa mining district, near Madero, State of Durango, Mexico. Link to MinDat.org Location Data.

Name Origin:

Named after the discovery locality.

Name Pronunciation:

Esperanzaite + Pronunciation

Synonym:

IMA1998-025

Esperanzaite Image

Images:

Esperanzaite

Comments: Pale blue-green botryoidal esperanzaite in rhyolite.
Location: Mina La Esperanza, Durango, Mexico. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Esperanzaite Crystallography

Axial Ratios:

a:b:c =0.9022:1:0.5171

Cell Dimensions:

a = 9.687, b = 10.737, c = 5.5523, Z = 2; beta = 105.32° V = 556.97 Den(Calc)= 3.36

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): 2.966(1), 2.7(0.9), 3.527(0.9),3.801(0.8), 4.796(0.8), 5.364(0.8),

Crystal Structure:

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Help on Above

Foord E E , Hughes J M , Cureton F E , Maxwell C H , Falster A U , Sommer A J , Hlava P F , The Canadian Mineralogist , 37 (1999) p.67-72, Esperanzaite, NaCa2Al2(AsO4)2F4(OH).2H2O, a new mineral species from, the La Esperanza mine, Mexico: Descriptive mineralogy and atomic arrangement, Locality: La Esperanza mine, Mexico

Physical Properties of Esperanzaite

Cleavage:

{100} Perfect

Color:

Blue green.

Density:

3.24

Diaphaneity:

Transparent to Translucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Botryoidal - "Grape-like" rounded forms (e.g.. malachite).

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Esperanzaite

Gladstone-Dale:

CI meas= 0.042 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.076 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1747,KPDmeas= 0.1812,KC= 0.1891
Ncalc = 1.61 - 1.64

Optical Data:

Biaxial (-), a=1.58, b=1.588, g=1.593, bire=0.0130, 2V(Calc)=76, 2V(Meas)=74. Dispersion r < v moderate.

Calculated Properties of Esperanzaite

Electron Density:

Bulk Density (Electron Density)=3.13 gm/cc
note: Specific Gravity of Esperanzaite =3.24 gm/cc.

Fermion Index:

Fermion Index = 0.0003429976
Boson Index = 0.9996570024

Photoelectric:

PE_Esperanzaite= 20.08 barns/electron
U=PE_Esperanzaite x rElectron Density= 62.74 barns/cc.

Radioactivity:

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

Esperanzaite Classification

Dana Class:

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

(42.04)where (AB)5 (XO4)2 Zq · x(H2O)

(42.04.02)Morinite Group

42.04.02.01 Morinite NaCa2Al2(PO4)2(F,OH)5•2(H2O) P 2₁/m 2/m

42.04.02.02 Esperanzaite! NaCa2Al2(AsO4)2F4(OH)•2(H2O) P 2₁/m 2/m

Strunz Class:

08.DM.05 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DM -With large and medium-sized cations, (OH, etc.):RO4 > 2:1

08.DM.05 Morinite NaCa2Al2(PO4)2(F,OH)5•2(H2O) P 2₁/m 2/m

08.DM.05 Esperanzaite! NaCa2Al2(AsO4)2F4(OH)•2(H2O) P 2₁/m 2/m

Other Esperanzaite Information

References:

NAME( CanMin 8/99) PHYS. PROP.(CanMin, 2/99) OPTIC PROP.(CanMin, 2/99)

See Also:

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

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Ask about Esperanzaite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Esperanzaite

NaCa2Al2(As+++++O4)2F4(OH)•2(H2O)
Dana No: 42.04.02.02 Strunz No: 08.DM.05
Locality:

Notes: