Hewettite Mineral Data

Hewettite Mineral Data +

General Hewettite Information

Chemical Formula:

CaV6O16·9(H2O)

Composition:

Molecular Weight = 763.85 gm

Calcium 5.25 % Ca 7.34 % CaO

Vanadium 40.01 % V 71.43 % V₂O₅

Hydrogen 2.38 % H 21.23 % H₂O

Oxygen 52.36 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaV⁵⁺₆O₁₆·9(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1914

Locality:

Link to MinDat.org Location Data.

Synonym:

ICSD 203169

PDF 35-564

Hewettite Image

Images:

Hewettite Fervanite

Comments: Spherical aggregate of acicular microcrystals of fervanite with blocky hewettite.
Location: Gold Quarry Mine, Carlin Trend, Eureka County, Nevada, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Hewettite

Comments: Red sub-metallic fibrous mats of hewettite on matrix.
Location: Cactus Rat Mine, Thompson's District, Grand Count, Utah, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Hewettite Crystallography

Axial Ratios:

a:b:c =3.503:1:3.1953

Cell Dimensions:

a = 12.25, b = 3.497, c = 11.174, Z = 1; beta = 97.25° V = 474.85 Den(Calc)= 2.67

Crystal System:

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

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

By Intensity(I/I_o): 11.03(1), 5.53(0.35), 2.1636(0.25),

Crystal Structure:

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Evans H T , The Canadian Mineralogist , 27 (1989) p.181-188, The crystal structure of hewettite, Note: sample Weeks number W-220-54, Locality: Colorado Plateau, USA

Physical Properties of Hewettite

Color:

Red.

Density:

2.5 - 2.6, Average = 2.54

Habit:

Acicular - Occurs as needle-like crystals.

Luminescence:

Non-fluorescent.

Luster:

Silky

Magnetism:

Nonmagnetic

Streak:

brownish red

Optical Properties of Hewettite

Gladstone-Dale:

CI meas= -0.315 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.256 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.4151,KPDmeas= 0.4346,KC= 0.3305

Optical Data:

Biaxial (-), a=1.77, b=2.18, g=2.35-2.4, bire=0.5800-0.6300

Calculated Properties of Hewettite

Electron Density:

r_electron=2.63 gm/cc
note: r_Hewettite=2.67 gm/cc.

Fermion Index

Fermion Index = 0.00132
Boson Index = 0.99868

Photoelectric:

PE_Hewettite= 8.20 barns/electron
U=PE_Hewettite x r_electron= 21.57 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Hewettite is Not Radioactive

Hewettite Classification

Dana Class:

47.3.1.1 (47)Vanadium Oxysalts

(47.3)(Hydrated)

(47.3.1)Dana Group

47.3.1.1 Hewettite CaV6O16·9(H2O) P 2/m 2/m

47.3.1.2 Metahewettite CaV6O16·3(H2O) A2/m 2/m

47.3.1.3 Barnesite Na2V6O16·3(H2O) P 2/m 2/m

47.3.1.4 Hendersonite Ca1.3V6O16·6(H2O) Pnam 2/m 2/m 2/m

47.3.1.5 Grantsite Na4CaxV2xV12-2xO32·8(H2O) C 2/m 2/m

Strunz Class:

IV/G.12-40 IV - Oxides

IV/G - Vanadiumoxides (with V4+/5+) Layered vanadates. Typical Vanadiumbronzes

IV/G.12 - Barnessite - Metahewettite series

IV/G.12-10 Barnesite Na2V6O16·3(H2O) P 2/m 2/m

IV/G.12-20 Grantsite Na4CaxV2xV12-2xO32·8(H2O) C 2/m 2/m

IV/G.12-30 Hendersonite Ca1.3V6O16·6(H2O) Pnam 2/m 2/m 2/m

IV/G.12-40 Hewettite CaV6O16·9(H2O) P 2/m 2/m

IV/G.12-50 Metahewettite CaV6O16·3(H2O) A2/m 2/m

Other Hewettite Information

References:

PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Hewettite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - WWW-MINCRYST 13 -École des Mines de Paris

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

Hewettite

CaV6O16·9(H2O)
Dana No: 47.3.1.1 Strunz No: IV/G.12-40
Locality:

Notes: