Dorrite Mineral Data

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General Dorrite Information

Chemical Formula:

Ca2Mg2Fe+++4(Al,Fe+++)4Si2O20

Composition:

Molecular Weight = 893.97 gm

Calcium 8.97 % Ca 12.55 % CaO

Magnesium 5.44 % Mg 9.02 % MgO

Aluminum 6.04 % Al 11.41 % Al₂O₃

Iron 37.48 % Fe 53.59 % Fe₂O₃

Silicon 6.28 % Si 13.44 % SiO₂

Oxygen 35.79 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂Mg₂Fe³⁺₆Al₂Si₂O₂₀

Environment:

Occurs in a paralava (pyrometamorhic melt rock) formed from burning coal beds.

IMA Status:

Approved IMA 1988

Locality:

Druham ranch, 25 km S of Gillette in the Powder River Basin, Wyoming. USA. Link to MinDat.org Location Data.

Name Origin:

Named for John A. Dorr (1922-1986), University of Michigan.

Name Pronunciation:

Dorrite

Dorrite Image

Images:

Dorrite

Comments: Dark brown micaceous dorrite (arrow) on matrix.
Location: Eicher, Sattel, Baden-Wurttemberg, Germany. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Dorrite Crystallography

Axial Ratios:

a:b:c =0.964:1:0.8276

Cell Dimensions:

a = 10.505, b = 10.897, c = 9.019, Z = 2; alpha = 106.26°, beta = 95.16°, gamma = 124.75° V = 811.06 Den(Calc)= 3.66

Crystal System:

TriclinicSpace Group: P1,P 1

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

By Intensity(I/I_o): 2.971(1), 2.515(0.8), 2.558(0.8),

Physical Properties of Dorrite

Cleavage:

{001} Distinct, {010} Distinct

Color:

Brownish black, Dark brown, Reddish brown.

Diaphaneity:

Subopaque

Fracture:

Irregular - Flat surfaces (not cleavage) fractured in an irregular pattern.

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Habit:

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

Hardness:

5 - Apatite

Luster:

Sub Metallic

Optical Properties of Dorrite

Gladstone-Dale:

CI calc= 0.174 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2188,KC= 0.2648
Ncalc = 2.02

Optical Data:

Biaxial (-), a=1.82, b=1.84, g=1.86, bire=0.0400, 2V(Calc)=88, 2V(Meas)=90.

Pleochroism (x):

red-orange brown.

Pleochroism (y):

yellowish brown.

Pleochroism (z):

greenish brown.

Calculated Properties of Dorrite

Electron Density:

Bulk Density (Electron Density)=3.73 gm/cc
note: Specific Gravity of Dorrite =3.84 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Dorrite= 12.91 barns/electron
U=PE_Dorrite x rElectron Density= 48.12 barns/cc.

Radioactivity:

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

Dorrite Classification

Dana Class:

69.02.01a.02 (69)Inosilicate Chains with Side Branches or Loops

(69.02)with P>2

(69.02.01a)Aenigmatite and related species (Aenigmatite subgroup)

69.02.01a.01 Aenigmatite (Na,Ca)4(Fe,Ti,Mg)12Si12O40 P1 1

69.02.01a.02 Dorrite Ca2Mg2Fe4(Al,Fe)4Si2O20 P1,P 1 Tri

69.02.01a.03 Hogtuvaite (Ca,Na)2(Fe,Fe,Ti,Mg,Mn)6(Si,Be,Al)6O20 P1 1

69.02.01a.04 Krinovite NaMg2CrSi3O10 P1 1

69.02.01a.05 Rhonite Ca2(Mg,Fe,Fe,Ti)6(Si,Al)6O20 P1 1

69.02.01a.06 Serendibite Ca2(Mg,Al)6(Si,Al,B)6O20 P1 1

69.02.01a.07 Welshite Ca4Mg9Sb3O4[Si6Be3AlFe2O36] P1 1

69.02.01a.08 Wilkinsonite Na2Fe4Fe2Si6O20 P1 1

69.02.01a.09 Makarochkinite! Ca2Fe4FeTiSi4BeAlO20 P1 1

Strunz Class:

09.DH.45 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DH -Inosilicates with 4-periodic single chains, Si4O12

09.DH.45 Aenigmatite (Na,Ca)4(Fe,Ti,Mg)12Si12O40 P1 1

09.DH.45 Dorrite Ca2Mg2Fe4(Al,Fe)4Si2O20 P1,P 1 Tri

09.DH.45 Krinovite NaMg2CrSi3O10 P1 1

09.DH.45 Rhonite Ca2(Mg,Fe,Fe,Ti)6(Si,Al)6O20 P1 1

09.DH.45 Sapphirine (Mg,Al)8(Al,Si)6O20 P1 1

09.DH.45 Serendibite Ca2(Mg,Al)6(Si,Al,B)6O20 P1 1

09.DH.45 Khmaralite! (Mg,Al,Fe)16(Al,Si,Be)12O40 P 2₁/c 2/m

09.DH.45 Makarochkinite! Ca2Fe4FeTiSi4BeAlO20 P1 1

09.DH.45 Welshite Ca4Mg9Sb3O4[Si6Be3AlFe2O36] P1 1

09.DH.45 Wilkinsonite Na2Fe4Fe2Si6O20 P1 1

Other Dorrite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Dorrite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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

Dorrite

Ca2Mg2Fe+++4(Al,Fe+++)4Si2O20
Dana No: 69.02.01a.02 Strunz No: 09.DH.45
Locality:

Notes: