Howardevansite Mineral Data

General Howardevansite Information

Chemical Formula:

NaCu++Fe+++2(VO4)3

Composition:

Molecular Weight = 543.05 gm

Sodium 4.23 % Na 5.71 % Na₂O

Vanadium 28.14 % V 50.24 % V₂O₅

Iron 20.57 % Fe 29.41 % Fe₂O₃

Copper 11.70 % Cu 14.65 % CuO

Oxygen 35.35 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

NaCuFe³⁺₂(VO₄)₃

Environment:

Forms by sublimation around furaroles on an andesitic volcano.

IMA Status:

Approved IMA 1988

Locality:

Izalco volcano, El Salvador. Link to MinDat.org Location Data.

Name Origin:

Named for Howard Tasker Evans, Jr. (1919-2000), American mineralogist and crystallographer, U.S.G.S., Reston, Virginia, USA.

Name Pronunciation:

Howardevansite + Pronunciation

Synonym:

ICSD 202529

PDF 42-1333

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Howardevansite Crystallography

Axial Ratios:

a:b:c =0.8388:1:0.6805

Cell Dimensions:

a = 8.198, b = 9.773, c = 6.651, Z = 2; alpha = 103.82°, beta = 101.99°, gamma = 106.74° V = 484.71 Den(Calc)= 3.72

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 3.093(1), 3.167(1), 1.659(0.7),

Crystal Structure:

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Hughes J M , Drexler J W , Campana C F , Malinconico M L , American Mineralogist , 73 (1988) p.181-186, Howardevansite, NaCuFe2(VO4)3, a new fumarolic sublimate from, Izalco volcano, El Salvador: Descriptive mineralogy and crystal structure, Note: Displacement ellipsoid for Na1 is not positive-definite

Physical Properties of Howardevansite

Cleavage:

None

Color:

Black.

Diaphaneity:

Opaque to translucent

Fracture:

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

Habit:

Tabular - Form dimensions are thin in one direction.

Luster:

Metallic

Streak:

red brown

Optical Properties of Howardevansite

Optical Data:

Biaxial (?)

NCalc= 2.14 - from Gladstone-Dale relationship (KC = 0.2992) where Ncalc=Dcalc*KC+1

RL Anisotrophism:

Moderate.

RL Color:

Medium gray.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Howardevansite in Air**
λ	R₁	R₂		∑ R₁(λ)	∑ R₂(λ)
481 nm	15.50	20.10

547 nm

15.00

18.40

591 nm

14.10

17.20

644 nm

13.50

17.10

**Calculated Relative Intensity Colors of Howardevansite in Air**
Relative Intensity	0%	70%	100%	140%	210%	280%	350%	420%	490%	560%	630%
R₁
R₂

Calculated Properties of Howardevansite

Electron Density: Bulk Density (Electron Density)=3.61 gm/cc
note: Specific Gravity of Howardevansite =3.81 gm/cc.

Fermion Index: Fermion Index = 0.0052336727
Boson Index = 0.9947663273

Photoelectric: PE_{Howardevansite}= 17.05 barns/electron
U=PE_{Howardevansite} x rElectron Density= 61.50 barns/cc.

Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Howardevansite is Not Radioactive

Howardevansite Classification

Dana Class: 38.05.03.01 (38)Anhydrous Phosphates, etc (38.05)with miscellaneous formulae (38.05.03)Dana Group

38.05.03.01 Howardevansite NaCuFe2(VO4)3 P1 1

Strunz Class: 08.AC.05 08 - PHOSPHATES, ARSENATES, VANADATES 08.A - Phosphates, etc. without additional anions, without H2O 08.AC -With medium-sized and large cations

08.AC.05 Howardevansite NaCuFe2(VO4)3 P1 1

Other Howardevansite Information

References: NAME( AntBidBlaNic4) PHYS. PROP.(Am.Min.,Vol.73,p181-186,1988) OPTIC PROP.(AntBidBlaNic4)

See Also: Links to other databases for Howardevansite :
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
15 - WWW-MINCRYST

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

Howardevansite

NaCu++Fe+++2(VO4)3
Dana No: 38.05.03.01 Strunz No: 08.AC.05
Locality:

Notes: