Help mindat.org|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on MindatThe Mindat Store
Minerals by PropertiesMinerals by ChemistryRandom MineralSearch by minIDLocalities Near MeSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportAdd Glossary Item
StatisticsMember ListBooks & MagazinesMineral Shows & EventsThe Mindat DirectoryHow to Link to MindatDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Enstatite

This page is currently not sponsored. Click here to sponsor this page.
Formula:
MgSiO3
System:
Orthorhombic
Colour:
White, yellowish green, ...
Lustre:
Vitreous, Pearly
Hardness:
5 - 6
Name:
From the Greek enstates - "opponent" for refractory nature under blowpipe flame.

Classification of Enstatite

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
9.DA.05

9 : SILICATES (Germanates)
D : Inosilicates
A : Inosilicates with 2-periodic single chains, Si2O6; pyroxene family
65.1.2.1

65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
1 : Single-Width Unbranched Chains, W=1 with chains P=2
14.4.2

14 : Silicates not Containing Aluminum
4 : Silicates of Mg
mindat.org URL:
http://www.mindat.org/min-1384.html
Please feel free to link to this page.

Occurrences of Enstatite

Geological Setting:
Magmatic mafic rocks

Physical Properties of Enstatite

Vitreous, Pearly
Diaphaneity (Transparency):
Translucent, Opaque
Comment:
Pearly on cleavage
Colour:
White, yellowish green, brown, greenish white or grey, olive-green
Streak:
Grey to white
Hardness (Mohs):
5 - 6
Tenacity:
Brittle
Cleavage:
Distinct/Good
Good on {210}
Parting:
on {100} and {010}
Fracture:
Irregular/Uneven
Density:
3.2 - 3.9 g/cm3 (Measured)    3.189 g/cm3 (Calculated)

Crystallography of Enstatite

Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pbca
Cell Parameters:
a = 18.23Å, b = 8.84Å, c = 5.19Å
Ratio:
a:b:c = 2.062 : 1 : 0.587
Unit Cell Volume:
V 836.39 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Prismatic crystals
Twinning:
The often reported "Simple and lamellar twinning on {100}" is no twinning (the symmetry plane is part of the crystal structure). Twinning may be confused with exsolution lamellae.

Crystallographic forms of Enstatite

Crystal Atlas:
Image Loading
Click on an icon to view
Enstatite no.12 - Goldschmidt (1913-1926)
Enstatite no.67 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by www.smorf.nl.

Toggle
Edge Lines | Miller Indicies | Axes

Transparency
Opaque | Translucent | Transparent

View
Along a-axis | Along b-axis | Along c-axis | Start rotation | Stop rotation
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Enstatite

Type:
Biaxial (+)
RI values:
nα = 1.650 - 1.668 nβ = 1.652 - 1.673 nγ = 1.659 - 1.679
2V:
Measured: 54° to 90°, Calculated: 58° to 86°
Max Birefringence:
δ = 0.009 - 0.011
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r < v weak

Chemical Properties of Enstatite

Formula:
MgSiO3
Essential elements:
All elements listed in formula:
Common Impurities:
Fe,Ca,Al,Co,Ni,Mn,Ti,Cr,Na,K

Relationship of Enstatite to other Species

Series:
Forms a series with Ferrosilite (see here)
Other Members of Group:
Donpeacorite(Mn2+,Mg)Mg[SiO3]2
FerrosiliteFeSiO3
9.DA.05Donpeacorite(Mn2+,Mg)Mg[SiO3]2
9.DA.05FerrosiliteFeSiO3
9.DA.10ClinoenstatiteMgSiO3
9.DA.10ClinoferrosiliteFe2+SiO3
9.DA.10KanoiteMn2+(Mg,Mn2+)Si2O6
9.DA.10Pigeonite(Mg,Fe2+,Ca)(Mg,Fe2+)Si2O6
9.DA.15Augite(Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
9.DA.15DiopsideCaMgSi2O6
9.DA.15EsseneiteCaFe3+[AlSiO6]
9.DA.15HedenbergiteCaFe2+Si2O6
9.DA.15JohannseniteCaMn2+Si2O6
9.DA.15PetedunniteCa(Zn,Mn2+,Mg,Fe2+)Si2O6
9.DA.15DavisiteCaScAlSiO6
9.DA.15KushiroiteCaAl[AlSiO6]
9.DA.15GrossmaniteCaTi3+ AlSiO6
9.DA.20Aegirine-augite(Na,Ca)(Fe3+,Fe2+,Mg,Al)Si2O6
9.DA.20Omphacite(Ca,Na)(Mg,Al)Si2O6
9.DA.25AegirineNaFe3+Si2O6
9.DA.25JadeiteNa(Al,Fe3+)Si2O6
9.DA.25Jervisite(Na,Ca,Fe2+)(Sc,Mg,Fe2+)Si2O6
9.DA.25KosmochlorNaCrSi2O6
9.DA.25NamansiliteNaMn3+Si2O6
9.DA.25NatalyiteNa(V3+,Cr)Si2O6
9.DA.30SpodumeneLiAlSi2O6
14.4.1ForsteriteMg2SiO4
14.4.3ClinoenstatiteMgSiO3
14.4.4ChrysotileMg3(Si2O5)(OH)4
14.4.5Clinochrysotile
14.4.6Orthochrysotile
14.4.7Parachrysotile
14.4.8LizarditeMg3(Si2O5)(OH)4
14.4.9TalcMg3(Si4O10)(OH)2
14.4.10SpadaiteMgSiO2(OH)2 · H2O (?)
14.4.11SepioliteMg4(Si6O15)(OH)2 · 6H2O
14.4.12LoughliniteNa2Mg3Si6O16 · 8H2O
14.4.13EifeliteKNa3Mg4Si12O30
14.4.14Stevensite(Ca,Na)xMg3-x(Si4O10)(OH)2
14.4.15AntigoriteMg3(Si2O5)(OH)4
14.4.16 Magnesio-anthophyllite

Other Names for Enstatite

Other Information

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Enstatite

Reference List:
Klaproth, M.H. (1810): Chemische Untersuchung des Bronzits, Beiträge zur chemischen Kenntniss der Mineralkörper, Fünfter Band, Rottmann Berlin, 32-36

Morimoto, N. and Koto, K. (1969) The crystal structure of orthoenstatite. Zeitschrift für Kristallographie: 129: 65-83.

Anastasiou, P. and Seifert, F. (1972) Solid solubility of Al2O3 in enstatite at high temperatures and 1-5 kb water pressure. Contributions to Mineralogy and Petrology: 34: 272-287.

Arima, M. and Onuma, K. (1977) The solubility of alumina in enstatite and the phase equilibria in the join MgSiO3-MgAl2SiO6 at 10-25 kbar. Contributions to Mineralogy and Petrology: 61: 251-265.

Hawthorne, F.C., and Ito, J. (1977) Synthesis and crystal structure refinement of transition-metal orthopyroxenes. I: orthoenstatite and (Mg,Mn,Co) orthopyroxene. Canadian Mineralogist: 15: 321-338.

Weidner, D.J., Wang, H., and Ito, J. (1978) Elasticity of orthoenstatite. Physics of the Earth and Planetary Interiors 17: 7-13.

Ralph, R.L. and Ghose, S. (1980) Enstatite, Mg2Si2O6: compressibility and crystal structure at 21 kbar (abs.). Eos: 61: 409.

Ohashi, Y. (1984) Polysynthetically-twinned structures of enstatite and wollastonite. Physics and Chemistry of Minerals: 10: 217-229.

Zeitschrift für Kristallographie (1986): 176: 159.

Duffy, T.S. and Vaughan, M.T. (1988) Elasticity of enstatite and its relationship to crystal structure. Journal of Geophysical Research: 93: 383-391.

Angel, R.J. and Hugh-Jones, D.A. (1994) Equation of state and thermodynamic properties of enstatite pyroxenes. Journal of Geophysical Research: 99: 19777-19783.

Hugh-Jones, D.A. and Angel, R.J. (1994) A compressional study of MgSiO3 orthoenstatite up to 8.5 GPa. American Mineralogist: 79: 405-410.

Yang, H. and Ghose, S. (1994) High-temperature single-crystal X-ray diffraction studies of the ortho-proto phase transition in enstatite, Mg2Si2O6 at 1360 K. Physics and Chemistry of Minerals: 22: 300-310.

Zhao, Y., Schiferl, D., and Shankland, T.J. (1995) A high P-T single-crystal X-ray diffraction study of thermoelasticity of MgSiO3 orthoenstatite. Pysics and Chemistry of Minerals: 22: 393-398.

Flesch, L.M., Li., B., and Liebermann, R.C. (1998) Sound velocities of polycrystalline MgSiO3-orthopyroxene to 10 GPa at room temperature. American Mineralogist: 83: 444-450.

Jackson, J.M., Sinogeikin, S.V., and Bass, J.D. (1999) Elasticity of MgSiO3 orthoenstatite. American Mineralogist: 84: 677-680.

Jackson, J.M., Palko, J., Sinogeikin, S.V., Bass, J.D., Andrault, D., and Zha, C. (2001) High-temperature single-crystal elasticity and thermal exansion of orthoenstatite. Eos (Fall Meeting Supplement), Abstract T31C-0853.

Angel, R.J. and Jackson, M.J. (2002) Elasticity and equation of state of orthoenstatite, MgSiO3. American Mineralogist: 87: 558-561.

Tarantino, S.C., Domeneghetti, M.C., Carpenter, M.A., Shaw, C.J.S., and Tazzoli, V. (2002a) Mixing properties of the enstatite-ferrosilite solid solution: I. A macroscopic perspective. European Journal of Mineralogy: 14: 525-536.

Tarantino, S.C., Boffa Ballaran, T., Carpenter, M.A., Domeneghetti, M.C., and Tazzoli, V. (2002b) Mixing properties of the enstatite-ferrosilite solid solution: II A microscopic perspective. Eurpean Journal of Mineralogy: 14: 537-547.

Lin, C.C. (2003) Pressure-induced metastable phase transition in orthoenstatite (MgSiO3) at room temperature: a Raman spectroscopic study. Journal of Solid State Chemistry: 174: 403-411.

Jackson, J.M., Sinogeikin, S.V., Carpenter, M.A., and Bass, J.D. (2004) Novel phase transition in orthoenstatite. American Mineralogist: 89: 239-245.

Kung, J., Li, B.S., Uchida, T., Wang, Y.B., Neuville, D., and Liebermann, R.C. (2004) In situ measurements of sound velocities and densities across the orthopyroxene - high-pressure clinopyroxene transition in MgSiO3 at high-pressure. Physics of the Earth and Planetary Interiors: 147: 27-44.

Nestola, F., Gatta, G.D., and Ballaran, T.B. (2006) The effect of Ca substitution on the elastic and structural behavior of orthoenstatite. American MIneralogist: 91: 809-815.

Internet Links for Enstatite

Specimens:
The following Enstatite specimens are currently listed for sale on minfind.com.

Localities for Enstatite

map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2015, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: September 4, 2015 02:33:26 Page generated: September 1, 2015 14:27:46