Magnesite Mineral Data

Magnesite Mineral Data +

General Magnesite Information

Chemical Formula:

MgCO3

Composition:

Molecular Weight = 84.31 gm

Magnesium 28.83 % Mg 47.80 % MgO

Carbon 14.25 % C 52.20 % CO₂

Oxygen 56.93 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg(CO₃)

Environment:

Evaporite mineral in sedimentary rocks.

IMA Status:

Valid Species (Pre-IMA) 1807

Locality:

Magnisía (Magnesia) Prefecture, Thessalia (Thessaly) Department, Greece Link to MinDat.org Location Data.

Name Origin:

Named after its chemical composition.

Synonym:

Bitter spar

ICSD 80870

PDF 8-479

Magnesite Image

Images:

Magnesite

Comments: Magnesite crystal group. The crystals have rhombic habit. The largest on this specimen is 3.7 cm across.
Location: Brumado Mine, Bahia, Brazil. Scale: Photo by John Veevaert.
© John Veevaert

Magnesite Crystallography

Axial Ratios:

a:c = 1:3.27001

Cell Dimensions:

a = 4.633, c = 15.15, Z = 6; V = 281.62 Den(Calc)= 2.98

Crystal System:

Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: R 3c

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

By Intensity(I/I_o): 2.742(1), 2.102(0.45), 1.7(0.35),

Forms:

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Forms: [ 1 0 0] [ 1 1 0] [ 0 1 1] [ 0 0 1]

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Crystal Structure:

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Graf D L , American Mineralogist , 46 (1961) p.1283-1316, Crystallographic tables for the rhombohedral carbonates

View Additional jPOWD Structure files for Magnesite
[1] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [2] [20] [21] [22] [23] [24] [3] [4] [5] [6] [7] [8] [9]

Physical Properties of Magnesite

Cleavage:

[1011] Perfect, [1011] Perfect, [1011] Perfect

Color:

Colorless, White, Grayish white, Yellowish white, Brownish white.

Density:

Diaphaniety:

Transparent to translucent to opaque

Fracture:

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

Habit:

Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Habit:

Massive - Fibrous - Distinctly fibrous fine-grained forms.

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Hardness:

4 - Fluorite

Luminescence:

None.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Magnesite

Gladstone-Dale:

CI meas= 0.021 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.014 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2029,KPDmeas= 0.2015,KC= 0.2057

Optical Data:

Uniaxial (-), e=1.7, w=1.508-1.51, bire=0.1900-0.1920.

Calculated Properties of Magnesite

Electron Density:

r_electron=2.97 gm/cc
note: r_Magnesite=2.98 gm/cc.

Fermion Index

Fermion Index = 0.03066
Boson Index = 0.96934

Photoelectric:

PE_Magnesite= 0.83 barns/electron
U=PE_Magnesite x r_electron= 2.45 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Magnesite is Not Radioactive

Magnesite Classification

Dana Class:

14.1.1.2 (14)Anhydrous Carbonates

(14.1)with Simple Formula A+ CO3

(14.1.1)Calcite Group (Trigonal: R3¯c)

14.1.1.1 Calcite CaCO3 R 3c 3 2/m

14.1.1.2 Magnesite MgCO3 R 3c 3 2/m

14.1.1.3 Siderite FeCO3 R 3c 3 2/m

14.1.1.4 Rhodochrosite MnCO3 R 3c 3 2/m

14.1.1.5 Sphaerocobaltite CoCO3 R 3c 3 2/m

14.1.1.6 Smithsonite ZnCO3 R 3c 3 2/m

14.1.1.7 Otavite CdCO3 R 3c 3 2/m

14.1.1.8 Gaspeite (Ni,Mg,Fe)CO3 R 3c 3 2/m

Strunz Class:

V/B.02-30 V - Nitrates, Carbonates and Borates

V/B - Waterfree carbonates [CO3]2- without unfamiliar anions

V/B.02 - Calcite group

V/B.02-10 Vaterite CaCO3 P 6₃/mmc 6/m 2/m 2/m

V/B.02-20 Calcite CaCO3 R 3c 3 2/m

V/B.02-30 Magnesite MgCO3 R 3c 3 2/m

V/B.02-40 Siderite FeCO3 R 3c 3 2/m

V/B.02-50 Rhodochrosite MnCO3 R 3c 3 2/m

V/B.02-60 Smithsonite ZnCO3 R 3c 3 2/m

V/B.02-70 Sphaerocobaltite CoCO3 R 3c 3 2/m

V/B.02-80 Gaspeite (Ni,Mg,Fe)CO3 R 3c 3 2/m

V/B.02-90 Otavite CdCO3 R 3c 3 2/m

Other Magnesite Information

References:

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

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Magnesite

MgCO3
Dana No: 14.1.1.2 Strunz No: V/B.02-30
Locality:

Notes: