Mathiasite Mineral Data

Mathiasite Mineral Data +

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General Mathiasite Information

Chemical Formula:

(K,Ca,Sr)(Ti,Cr,Fe,Mg)21O38

Composition:

Molecular Weight = 1,682.56 gm

Potassium 1.39 % K 1.68 % K₂O

Strontium 0.52 % Sr 0.62 % SrO

Calcium 0.71 % Ca 1.00 % CaO

Magnesium 0.72 % Mg 1.20 % MgO

Titanium 36.99 % Ti 61.72 % TiO₂

Chromium 18.54 % Cr 24.25 % CrO

Iron 4.98 % Fe 6.41 % FeO

Oxygen 36.13 % O

______ ______

100.00 % 96.86 % = TOTAL OXIDE

Empirical Formula:

K_0.6Ca_0.3Sr_0.1Ti₁₃Cr₆Fe²⁺_1.5Mg_0.5O₃₈

Environment:

In kimberlite.

IMA Status:

Approved IMA 1983

Locality:

Jagersfontein mine, Orange Free State, South Africa. Link to MinDat.org Location Data.

Name Origin:

Named for Frances Celia Morna Mathias (1913-), British-South African geochemist, University of Capetown, South Africa.

Synonym:

ICSD 35353

PDF 46-1468

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Mathiasite Crystallography

Axial Ratios:

a:c = 1:1.99324

Cell Dimensions:

a = 10.36, c = 20.65, Z = 3; V = 1,919.42 Den(Calc)= 4.37

Crystal System:

Trigonal - RhombohedralH-M Symbol ( 3) Space Group: R 3

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

By Intensity(I/I_o): 1.44(1), 2.14(1), 2.25(0.9),

Physical Properties of Mathiasite

Cleavage:

None

Color:

Black.

Density:

4.6

Diaphaniety:

Opaque

Fracture:

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

Hardness:

7.5 - Garnet

Luster:

Metallic

Streak:

gray

Optical Properties of Mathiasite

Dichroism (e):

dark tan.

Dichroism (w):

weaker dark tan.

Optical Data:

Uniaxial (?).

NCalc= 2.36 - from Gladstone-Dale relationship (KC = 0.3122) where Ncalc=Dcalc*KC+1
NCalc= 2.44 - from Gladstone-Dale relationship (KC = 0.3122) where Ncalc=Dmeas*KC+1

RL Anisotrophism:

Moderate, brownish tan to dark brown.

RL Color:

Tan.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Mathiasite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	20.10	20.80
420 nm	19.50	20.20
440 nm	19.00	19.70
460 nm	18.50	19.20
480 nm	18.10	18.60
500 nm	17.70	18.40
520 nm	17.40	18.20
540 nm	17.20	17.90
560 nm	16.90	17.70
580 nm	16.80	17.60
600 nm	16.60	17.40
620 nm	16.50	17.40
640 nm	16.50	17.30
660 nm	16.50	17.30
680 nm	16.40	17.30
700 nm	16.40	17.30

**Calculated Relative Intensity Colors of Mathiasite in Air**
Relative Intensity	0%	60%	100%	120%	180%	240%	300%	360%	420%	480%	520%
R₁
R₂

Calculated Properties of Mathiasite

Electron Density:

r_electron=4.16 gm/cc
note: r_Mathiasite=4.37 gm/cc.

Fermion Index

Fermion Index = 0.06777
Boson Index = 0.93223

Photoelectric:

PE_Mathiasite= 12.77 barns/electron
U=PE_Mathiasite x r_electron= 53.09 barns/cc.

Radioactivity:

GRapi = 19.11 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Mathiasite - barely detectable

Mathiasite Classification

Dana Class:

8.5.1.7 (8)Multiple Oxides with Nb, Ta, and Ti

(8.5)Dana Type

(8.5.1)Crichtonite group (ABC18 T2 O38)

8.5.1.1 Landauite NaMnZn2(Ti,Fe)6Ti12O38 R 3 3

8.5.1.2 Loveringite (Ca,Ce)(Ti,Fe,Cr,Mg)21O38 R 3 3

8.5.1.3 Crichtonite (Sr,La,Ce,Y)(Ti,Fe,Mn)21O38 R 3 3

8.5.1.4 Senaite Pb(Ti,Fe,Mn)21O38 R 3 3

8.5.1.5 Davidite-(La) (La,Ce,Ca)(Y,U)(Ti,Fe)20O38 R 3 3

8.5.1.6 Davidite-(Ce) (Ce,La)(Y,U)(Ti,Fe)20O38 R 3 3

8.5.1.7 Mathiasite (K,Ca,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

8.5.1.8 Lindsleyite (Ba,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

8.5.1.9 Dessauite! (Sr,Pb)(Y,U)(Ti,Fe)20O38 P 3 3

8.5.1.10 Cleusonite! Pb(U,U)(Ti,Fe2,Fe3)20(O,OH)38 R 3 3

8.5.1.11 Gramaccioliite-(Y)! (Pb,Sr)(Y,Mn)Fe2(Ti,Fe)18O38 R 3 3

Strunz Class:

IV/C.09-20 IV - Oxides

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

IV/C.09 - Crichtonite group

IV/C.09-10 Landauite NaMnZn2(Ti,Fe)6Ti12O38 R 3 3

IV/C.09-20 Mathiasite (K,Ca,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

IV/C.09-30 Loveringite (Ca,Ce)(Ti,Fe,Cr,Mg)21O38 R 3 3

IV/C.09-40 Crichtonite (Sr,La,Ce,Y)(Ti,Fe,Mn)21O38 R 3 3

IV/C.09-45 Dessauite! (Sr,Pb)(Y,U)(Ti,Fe)20O38 P 3 3

IV/C.09-50 Lindsleyite (Ba,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

IV/C.09-60 Davidite-(La) (La,Ce,Ca)(Y,U)(Ti,Fe)20O38 R 3 3

IV/C.09-62 Gramaccioliite-(Y)! (Pb,Sr)(Y,Mn)Fe2(Ti,Fe)18O38 R 3 3

IV/C.09-70 Davidite-(Ce) (Ce,La)(Y,U)(Ti,Fe)20O38 R 3 3

IV/C.09-80 Senaite Pb(Ti,Fe,Mn)21O38 R 3 3

Other Mathiasite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3)

See Also:

Links to other databases for Mathiasite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - WWW-MINCRYST 13 -École des Mines de Paris

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Mathiasite

(K,Ca,Sr)(Ti,Cr,Fe,Mg)21O38
Dana No: 8.5.1.7 Strunz No: IV/C.09-20
Locality:

Notes: