Phenakite Mineral Data

General Phenakite Information

Chemical Formula:

Be2SiO4

Composition:

Molecular Weight = 110.11 gm

Beryllium 16.37 % Be 45.43 % BeO

Silicon 25.51 % Si 54.57 % SiO₂

Oxygen 58.12 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Be₂(SiO₄)

Environment:

Alpine fissures, pegmatites, and hydrothermally altered rocks.

IMA Status:

Valid Species (Pre-IMA) 1833

Locality:

Takovaya, Ekaterinburg (Sverdlovsk), Ural Mts, Russia Link to MinDat.org Location Data.

Name Origin:

From the Greek phenakos - "deceiver", in allusion to its similarity to quartz when colorless.

Name Pronunciation:

Phenakite + Pronunciation

Synonym:

ICSD 64949

PDF 9-431

Phenakite Image

Images:

Phenakite

Comments: Prismatic, terminated crystal of phenakite on matrix.
Location: Mt Antero, Chaffee County, Colorado, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Phenakite Crystallography

Axial Ratios:

a:c = 1:0.66164

Cell Dimensions:

a = 12.472, c = 8.252, Z = 18; V = 1,111.63 Den(Calc)= 2.96

Crystal System:

Trigonal - RhombohedralH-M Symbol ( 3) Space Group: R 3

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

By Intensity(I/I_o): 3.119(1), 3.66(0.8), 2.518(0.75),

Forms:

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Forms: ( 1 1 1) ( 2 1 0) ( 1 2 0)

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Crystal Structure:

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Downs J W , Gibbs G V , American Mineralogist , 72 (1987) p.769-777, An exploratory examination of the electron density and electrostatic potential, of phenakite

View Additional jPOWD Structure files for Phenakite
[1] [2] [3] [4] [5] [6] [7] [8]

Physical Properties of Phenakite

Cleavage:

{1120} Distinct

Color:

Colorless, Wine yellow, Yellow, Pink, Pinkish red.

Density:

2.97 - 3, Average = 2.98

Diaphaneity:

Transparent to subtranslucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Massive - Fibrous - Distinctly fibrous fine-grained forms.

Hardness:

7.5-8

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Phenakite

Gladstone-Dale:

CI meas= 0.003 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.005 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2236,KPDmeas= 0.2218,KC= 0.2225
Ncalc = 1.66 - 1.67

Optical Data:

Uniaxial (+), w=1.654, e=1.67, bire=0.0160.

Calculated Properties of Phenakite

Electron Density:

Bulk Density (Electron Density)=2.93 gm/cc
note: Specific Gravity of Phenakite =2.99 gm/cc.

Fermion Index:

Fermion Index = 0.17
Boson Index = 0.83

Photoelectric:

PE_Phenakite= 1.14 barns/electron
U=PE_Phenakite x rElectron Density= 3.33 barns/cc.

Radioactivity:

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

Phenakite Classification

Dana Class:

51.01.01.01 (51)Nesosilicate Insular SiO4 Groups Only

(51.01)with cations in [4] coordination

(51.01.01)Phenakite group

51.01.01.01 Phenakite Be2SiO4 R 3 3

51.01.01.02 Willemite Zn2SiO4 R 3 3

51.01.01.03 Eucryptite LiAlSiO4 R 3 3

Strunz Class:

09.AA.05 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AA -Nesosilicates without additional anions;

09.AA.05 Eucryptite LiAlSiO4 R 3 3

09.AA.05 Phenakite Be2SiO4 R 3 3

09.AA.05 Willemite Zn2SiO4 R 3 3

Other Phenakite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Phenakite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (MinSocAm)
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info
14 - Scandinavian mineral gallery
15 - Tradeshop.com - The Rainbow of Gems
16 - WWW-MINCRYST

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Ask about Phenakite 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 Phenakite Specimen Label here :

Phenakite

Be2SiO4
Dana No: 51.01.01.01 Strunz No: 09.AA.05
Locality:

Notes: