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)

Environment:

Alteration product of patronite.

IMA Status:

Valid Species (Pre-IMA) 1914

Locality:

Minasragra, 46 km from Cerro de Pasco, Peru. Link to MinDat.org Location Data.

Name Origin:

Named for Donnel Foster Hewett (1881-1971), geologist with the U.S. Geological Survey, who described the mineralogy of Minasragra, Peru.

Name Pronunciation:

Hewettite + Pronunciation

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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drag2 - RMB Resize/Rotate
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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
Ncalc = 1.83 - 1.88

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:

Bulk Density (Electron Density)=2.63 gm/cc
note: Specific Gravity of Hewettite =2.67 gm/cc.

Fermion Index:

Fermion Index = 0.0013260922
Boson Index = 0.9986739078

Photoelectric:

PE_Hewettite= 8.20 barns/electron
U=PE_Hewettite x rElectron Density= 21.57 barns/cc.

Radioactivity:

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

Hewettite Classification

Dana Class:

47.03.01.01 (47)Vanadium Oxysalts

(47.03)(Hydrated)

(47.03.01)Hewettite Group

47.03.01.01 Hewettite CaV6O16•9(H2O) P 2/m 2/m

47.03.01.02 Metahewettite CaV6O16•3(H2O) A2/m 2/m

47.03.01.03 Barnesite Na2V6O16•3(H2O) P 2/m 2/m

47.03.01.04 Hendersonite Ca1.3V6O16•6(H2O) Pnam 2/m 2/m 2/m

47.03.01.05 Grantsite Na4CaxV2xV12-2xO32•8(H2O) C 2/m 2/m

Strunz Class:

04.HE.15 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.H - V[5,6] Vanadates

04.HE -Phyllovanadates

04.HE.15 Hewettite CaV6O16•9(H2O) P 2/m 2/m

04.HE.15 Metahewettite CaV6O16•3(H2O) A2/m 2/m

Other Hewettite Information

References:

NAME( AntBidBlaNic4) 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 - 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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Ask about Hewettite 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 Hewettite Specimen Label here :

Hewettite

CaV6O16•9(H2O)
Dana No: 47.03.01.01 Strunz No: 04.HE.15
Locality:

Notes: