Cordierite Mineral Data

[Newest Minerals] [Equipment] [Analytical Services] [About Us] [Mineral Gallery] [eBay Store]
See Also: [Diamond Crystals] [Mineral News] [Hudson Institute] [Minerals on CDROM]
Rare Minerals, Meteorites, Equipment and Analytical Services
Excalibur Mineral Company, World leaders in the supply of rare species
Serving the scientific and collector communities since 1974

General Cordierite Information

Chemical Formula:

Mg2Al4Si5O18

Composition:

Molecular Weight = 584.95 gm

Magnesium 8.31 % Mg 13.78 % MgO

Aluminum 18.45 % Al 34.86 % Al₂O₃

Silicon 24.01 % Si 51.36 % SiO₂

Oxygen 49.23 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₂Al₄Si₅O₁₈

Environment:

Magmatic, metamorphic, and pegmatitic rocks.

IMA Status:

Valid Species (Pre-IMA) 1813

Locality:

Bodenmais, Germany. Link to MinDat.org Location Data.

Name Origin:

From the French mining engineer and geologist P. L. A. Cordier (1777-1861).

Name Pronunciation:

Cordierite + Pronunciation

Synonym:

Dichroite

ICSD 100250

Iolite

PDF 12-303

Cordierite Image

Images:

Cordierite

Comments: Brown rectangular cordierite crystals in matrix. These crystals are not gemmy enough to be called iolite.
Location: Richmond Soapstone Quarry, Richmond, Cheshire Co., New Hampshire, USA. Scale: 24x20x15 mm.
© John Betts - Fine Minerals

Images:

Cordierite

Comments: Piece of near-gem-quality glassy gray-blue cordierite with some yellowish internal reflections.
Location: Mt. Bity District, Madagascar. Scale: Overall: 2 x 1 x 1.5 cm.
© Tom Loomis / Dakota Matrix

Cordierite Crystallography

Axial Ratios:

a:b:c =1.7479:1:0.954

Cell Dimensions:

a = 17.13, b = 9.8, c = 9.35, Z = 4; V = 1,569.62 Den(Calc)= 2.48

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: C ccm

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

By Intensity(I/I_o): 3.13(1), 8.45(0.8), 8.54(0.8),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Gibbs G V , American Mineralogist , 51 (1966) p.1068-1087, The polymorphism of cordierite I: The crystal structure of low cordierite

View Additional jPOWD Structure files for Cordierite
[1] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [2] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [3] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [4] [40] [41] [42] [43] [44] [45] [46] [47] [5] [6] [7] [8] [9]

Physical Properties of Cordierite

Cleavage:

{010} Poor

Color:

Colorless, Pale blue, Violet, Yellow, Gray.

Density:

2.55 - 2.75, Average = 2.65

Diaphaneity:

Transparent to translucent

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

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

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

7 - Quartz

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Cordierite

Gladstone-Dale:

CI meas= -0.008 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.077 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2224,KPDmeas= 0.2081,KC= 0.2065
Ncalc = 1.51 - 1.57

Optical Data:

Biaxial (-), a=1.527-1.56, b=1.532-1.574, g=1.538-1.578, bire=0.0110-0.0180, 2V(Calc)=54-86, 2V(Meas)=75-89. Dispersion weak, r < v.

Pleochroism (x):

colorless, pale yellow, or pale yellow.

Pleochroism (y):

colorless, violet, or blue.

Calculated Properties of Cordierite

Electron Density:

Bulk Density (Electron Density)=2.63 gm/cc
note: Specific Gravity of Cordierite =2.65 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Cordierite= 1.65 barns/electron
U=PE_Cordierite x rElectron Density= 4.32 barns/cc.

Radioactivity:

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

Cordierite Classification

Dana Class:

61.02.01.01 (61)Cyclosilicate Six-Membered Rings

(61.02)with Al substituted rings

(61.02.01)Cordierite group

61.02.01.01 Cordierite Mg2Al4Si5O18 C ccm 2/m 2/m 2/m

61.02.01.02 Sekaninaite (Fe,Mg)2Al4Si5O18 C ccm 2/m 2/m 2/m

Strunz Class:

09.CJ.10 09 - SILICATES (Germanates)

09.C - Cyclosilicates

09.CJ -[Si6O18]12- 6-membered single rings (sechser-Einfachringe),

09.CJ.10 Cordierite Mg2Al4Si5O18 C ccm 2/m 2/m 2/m

09.CJ.10 Sekaninaite (Fe,Mg)2Al4Si5O18 C ccm 2/m 2/m 2/m

Other Cordierite Information

Search for Cordierite using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Cordierite :

AA Mineral Specimens

B & L Fine Minerals

Crystalarium.com

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

Dakota Matrix

Desert Winds Gems and Minerals

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

Wrights Rock Shop

Translate Cordierite Mineral Data :

Ask about Cordierite 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 Cordierite Specimen Label here :

Cordierite

Mg2Al4Si5O18
Dana No: 61.02.01.01 Strunz No: 09.CJ.10
Locality:

Notes: