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:

Magnisï¿½a (Magnesia) Prefecture, Thessalia (Thessaly) Department, Greece Link to MinDat.org Location Data.

Name Origin:

Named after its chemical composition.

Name Pronunciation:

Magnesite + Pronunciation

Synonym:

Bitter spar

Hoshiite - Ni-bearing magnesite

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 Scalenohedral H-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:

Mouse
Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize
Keyboard
S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu
Help on Above

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

Warning: this java applet does not work in some browsers because of security restrictions.

Physical Properties of Magnesite

Cleavage:

{1011} Perfect, {1011} Perfect, {1011} Perfect

Color:

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

Density:

Diaphaneity:

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:

Fluorescent, Short UV=blue white, Long UV=bright blue white.

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
Ncalc = 1.61 - 1.62

Optical Data:

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

Calculated Properties of Magnesite

Electron Density:

Bulk Density (Electron Density)=2.97 gm/cc
note: Specific Gravity of Magnesite =2.98 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Magnesite= 0.83 barns/electron
U=PE_Magnesite x rElectron Density= 2.45 barns/cc.

Radioactivity:

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

Magnesite Classification

Dana Class:

14.01.01.02 (14)Anhydrous Carbonates

(14.01)with Simple Formula A+ CO3

(14.01.01)Calcite Group (Trigonal: R-3c)

14.01.01.01 Calcite CaCO3 R 3c 3 2/m

14.01.01.02 Magnesite MgCO3 R 3c 3 2/m

14.01.01.03 Siderite FeCO3 R 3c 3 2/m

14.01.01.04 Rhodochrosite MnCO3 R 3c 3 2/m

14.01.01.05 Sphaerocobaltite CoCO3 R 3c 3 2/m

14.01.01.06 Smithsonite ZnCO3 R 3c 3 2/m

14.01.01.07 Otavite CdCO3 R 3c 3 2/m

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

Strunz Class:

05.AB.05 05 - CARBONATES (NITRATES)

05.A - Carbonates without additional anions, without H2O

05.AB -Alkali-earth (and other M2+) carbonates

05.AB.05 Calcite CaCO3 R 3c 3 2/m

05.AB.05 Gaspeite (Ni,Mg,Fe)CO3 R 3c 3 2/m

05.AB.05 Magnesite MgCO3 R 3c 3 2/m

05.AB.05 Rhodochrosite MnCO3 R 3c 3 2/m

05.AB.05 Otavite CdCO3 R 3c 3 2/m

05.AB.05 Sphaerocobaltite CoCO3 R 3c 3 2/m

05.AB.05 Siderite FeCO3 R 3c 3 2/m

05.AB.05 Smithsonite ZnCO3 R 3c 3 2/m

Other Magnesite Information

References:

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

Search for Magnesite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Magnesite :

Ask about Magnesite 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 Magnesite Specimen Label here :

Magnesite

MgCO3
Dana No: 14.01.01.02 Strunz No: 05.AB.05
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.