Enstatite Mineral Data

General Enstatite Information

Chemical Formula:

Mg2Si2O6

Composition:

Molecular Weight = 200.78 gm

Magnesium 24.21 % Mg 40.15 % MgO

Silicon 27.98 % Si 59.85 % SiO₂

Oxygen 47.81 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₂Si₂O₆

Environment:

Magmatic mafic rocks.

IMA Status:

Valid Species (Pre-IMA) 1855

Locality:

Common worldwide. Link to MinDat.org Location Data.

Name Origin:

From the Greek enstates - "opponent."

Name Pronunciation:

Enstatite + Pronunciation

Synonym:

Bronzite - bronze brown

ICSD 37313

Orthoenstatite

PDF 19-768

Enstatite Image

Images:

Enstatite

Comments: Single, terminated, brown, transparent to translucent enstatite crystal.
Location: Mpwa-Mpwa, Tanzania. Scale: 17x17x27 mm.
© Dan Weinrich

Enstatite Crystallography

Axial Ratios:

a:b:c =2.0701:1:0.5888

Cell Dimensions:

a = 18.228, b = 8.805, c = 5.185, Z = 8; V = 832.18 Den(Calc)= 3.20

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P bca

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

By Intensity(I/I_o): 3.167(1), 2.872(0.85), 2.494(0.5),

Physical Properties of Enstatite

Cleavage:

{110} Distinct, {010} Distinct

Color:

White, Yellowish green, Brown, Greenish white, Gray.

Density:

3.1 - 3.3, Average = 3.2

Diaphaneity:

Translucent to opaque

Fracture:

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

Habit:

Lamellar - Thin laminae producing a lamellar structure.

Habit:

Massive - Fibrous - Distinctly fibrous fine-grained forms.

Hardness:

5.5 - Knife Blade

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Pearly

Streak:

gray

Optical Properties of Enstatite

Gladstone-Dale:

CI meas= -0.012 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2073,KPDmeas= 0.2073,KC= 0.2048
Ncalc = 1.63 - 1.68

Optical Data:

Biaxial (+), a=1.65-1.668, b=1.652-1.673, g=1.659-1.679, bire=0.0090-0.0110, 2V(Calc)=58-86, 2V(Meas)=54-90. Dispersion weak, r < v.

Calculated Properties of Enstatite

Electron Density:

Bulk Density (Electron Density)=3.19 gm/cc
note: Specific Gravity of Enstatite =3.20 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Enstatite= 1.61 barns/electron
U=PE_Enstatite x rElectron Density= 5.13 barns/cc.

Radioactivity:

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

Enstatite Classification

Dana Class:

65.01.02.01 (65)Inosilicate Single-Width Unbranched Chains, W=1

(65.01)with chains P=2

(65.01.02)Orthopyroxenes

65.01.02.01 Enstatite Mg2Si2O6 P bca 2/m 2/m 2/m

65.01.02.02 Ferrosilite (Fe,Mg)2Si2O6 P bca 2/m 2/m 2/m

65.01.02.03 Donpeacorite (Mn,Mg)MgSi2O6 P bca 2/m 2/m 2/m

Strunz Class:

09.DA.05 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DA -Inosilicates with 2-periodic single chains, Si2O6; pyroxene family

09.DA.05 Donpeacorite (Mn,Mg)MgSi2O6 P bca 2/m 2/m 2/m

09.DA.05 Akimotoite! (Mg,Fe)SiO3 R 3 3

09.DA.05 Enstatite Mg2Si2O6 P bca 2/m 2/m 2/m

09.DA.05 Ferrosilite (Fe,Mg)2Si2O6 P bca 2/m 2/m 2/m

Other Enstatite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

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

Enstatite

Mg2Si2O6
Dana No: 65.01.02.01 Strunz No: 09.DA.05
Locality:

Notes:

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