Corundum Mineral Data

Corundum Mineral Data +

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General Corundum Information

Chemical Formula:

Al2O3

Composition:

Molecular Weight = 101.96 gm

Aluminum 52.93 % Al 100.00 % Al₂O₃

Oxygen 47.07 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

(Al₂O₃)

Environment:

Contact and regionally metamorphosed rocks.

IMA Status:

Valid Species (Pre-IMA) Prehistoric

Locality:

Tchainit and Yakutia, Russia. Link to MinDat.org Location Data.

Name Origin:

Probably derived from the Sanskrit, kuruvinda, meaning "ruby."

Synonym:

ICSD 31545

Leucosapphire - colorless

PDF 43-1484

Ruby - red

Sapphire - blue

Corundum Image

Images:

Corundum

Comments: corundum (variety Sapphire).
Location: Miass, Urals, Russia. Scale: 10 x 8 cm.
© Fabre Minerals

Images:

Corundum Zincohogbomite-2N2S

Comments: Thin-Section (Plane Polarized Light) of a brown, twinned zincoh?gbomite-2N2S crystal with blue corundum.
Location: Mikro-Lakka Emery deposit, Kerketeas Mt, S?mos Island, Aegean Islands Department, Greece. Scale: Picture size 1.1 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Corundum

Comments: Bright red ruby corundum crystals in white marble matrix.
Location: Jagdalak (Jagdalek; Jagdalik) Ruby Mine, Sorobi District, Konar (Kunar; Konarh; Konarha; Nuristan) Province, Afghanistan. Scale: 4x3.5x3 cm.
© John Betts - Fine Minerals

Corundum Crystallography

Axial Ratios:

a:c = 1:2.72995

Cell Dimensions:

a = 4.751, c = 12.97, Z = 6; V = 253.54 Den(Calc)= 4.01

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): 2.085(1), 2.552(0.9), 1.601(0.8),

Forms:

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Forms: [ 1 1 4] [ 2 0 1] [ 1 0 2] [ 1 0 1] [ 0 0 1]

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Crystal Structure:

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Lewis J , Schwarzenbach D , Flack H D , Acta Crystallographica, Section A , 38 (1982) p.733-739, Electric field gradients and charge density in corundum alpha-Al2O3

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

Physical Properties of Corundum

Cleavage:

None

Color:

Blue, Red, Yellow, Brown, Gray.

Density:

4 - 4.1, Average = 4.05

Diaphaniety:

Transparent to translucent

Fracture:

Tough - Difficult to break apart as shown by fibrous minerals and most metals.

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Habit:

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

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

9 - Corundum

Luminescence:

None.

Luster:

Vitreous (Glassy)

Magnetism:

Nonmagnetic

Streak:

none

Optical Properties of Corundum

Gladstone-Dale:

CI meas= 0.089 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.08 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1905,KPDmeas= 0.1886,KC= 0.207

Optical Data:

Uniaxial (-), e=1.76, w=1.768, bire=0.0080.

Calculated Properties of Corundum

Electron Density:

r_electron=3.93 gm/cc
note: r_Corundum=4.01 gm/cc.

Fermion Index

Fermion Index = 0.00022
Boson Index = 0.99978

Photoelectric:

PE_Corundum= 1.54 barns/electron
U=PE_Corundum x r_electron= 6.08 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Corundum is Not Radioactive

Corundum Classification

Dana Class:

4.3.1.1 (4)Simple Oxides

(4.3)with a cation charge of 3+ (A+++2 O3)

(4.3.1)Corundum-Hematite group (Rhombohedral: R3¯c)

4.3.1.1 Corundum Al2O3 R 3c 3 2/m

4.3.1.2 Hematite Fe2O3 R 3c 3 2/m

4.3.1.3 Eskolaite Cr2O3 R 3c 3 2/m

4.3.1.4 Karelianite V2O3 R 3c 3 2/m

Strunz Class:

IV/C.04-10 IV - Oxides

IV/C - Oxides with metal : oxygen = 2:3 (M2O3 and related compounds)

IV/C.04 - Hematite group

IV/C.04-10 Corundum Al2O3 R 3c 3 2/m

IV/C.04-20 Hematite Fe2O3 R 3c 3 2/m

IV/C.04-30 Eskolaite Cr2O3 R 3c 3 2/m

IV/C.04-40 Karelianite V2O3 R 3c 3 2/m

Other Corundum Information

References:

NAME( Sinkankas66) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Sinkankas66)

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

Corundum

Al2O3
Dana No: 4.3.1.1 Strunz No: IV/C.04-10
Locality:

Notes: