Homilite Mineral Data

Homilite Mineral Data +

General Homilite Information

Chemical Formula:

Ca2(Fe++,Mg)B2Si2O10

Composition:

Molecular Weight = 365.90 gm

Calcium 21.91 % Ca 30.65 % CaO

Magnesium 1.66 % Mg 2.75 % MgO

Iron 11.45 % Fe 14.73 % FeO

Silicon 15.35 % Si 32.84 % SiO₂

Boron 5.91 % B 19.03 % B₂O₃

Oxygen 43.73 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂Fe²⁺_0.75Mg_0.25B₂Si₂O₁₀

IMA Status:

Valid Species (Pre-IMA) 1896

Locality:

Stoko island, Langesundfiord, southern Norway. Link to MinDat.org Location Data.

Synonym:

ICSD 47157

PDF 36-430

Homilite Image

Images:

Homilite

Comments: Brown crystalline masses of homilite in white feldspar.
Location: Aroy, Langesundfjord, Telemark, Norway. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Homilite Crystallography

Axial Ratios:

a:b:c =1.2774:1:0.6261

Cell Dimensions:

a = 9.67, b = 7.57, c = 4.74, Z = 2; beta = 90.367° V = 346.97 Den(Calc)= 3.50

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/a

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

By Intensity(I/I_o): 2.52(1), 3.1(1), 2.83(0.9),

Physical Properties of Homilite

Cleavage:

None

Color:

Black, Blackish brown.

Density:

3.38

Diaphaniety:

Translucent to subtranslucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

5 - Apatite

Luster:

Vitreous (Glassy)

Optical Properties of Homilite

Gladstone-Dale:

CI meas= -0.039 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.003 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2074,KPDmeas= 0.2148,KC= 0.2068

Optical Data:

Biaxial (+), a=1.715, b=1.725, g=1.738, bire=0.0230, 2V(Calc)=84, 2V(Meas)=80.

Calculated Properties of Homilite

Electron Density:

r_electron=3.45 gm/cc
note: r_Homilite=3.50 gm/cc.

Fermion Index

Fermion Index = 0.02352
Boson Index = 0.97648

Photoelectric:

PE_Homilite= 6.78 barns/electron
U=PE_Homilite x r_electron= 23.41 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Homilite is Not Radioactive

Homilite Classification

Dana Class:

54.2.1b.5 (54)Nesosilicate Borosilicates and Some Beryllosilicates

(54.2)with B in [4] coordination

(54.2.1b)Datolite group (Homilite series)

54.2.1b.1 Bakerite Ca4B4(BO4)(SiO4)3(OH)3·(H2O) P 2₁/c 2/m

54.2.1b.2 Gadolinite-(Ce) (Ce,La,Nd,Y)2FeBe2Si2O10 P 2₁/c 2/m

54.2.1b.3 Gadolinite-(Y) Y2FeBe2Si2O10 P 2₁/a 2/m

54.2.1b.4 Calciogadolinite* CaREE(Fe)Be2Si2O10 P 2₁/a 2/m

54.2.1b.5 Homilite Ca2(Fe,Mg)B2Si2O10 P 2₁/a 2/m

54.2.1b.6 Minasgeraisite-(Y) CaY2Be2Si2O10 P 2₁/a 2/m

Strunz Class:

VIII/B.29-30 VIII - Silicates

VIII/B - Nesosubsilicates, with anions unfamiliar to tetraheders, with beryllium and boron

VIII/B.29 - Datolite/Gadolinite group

VIII/B.29-10 Datolite CaBSiO4(OH) P 2₁/c 2/m

VIII/B.29-20 Bakerite Ca4B4(BO4)(SiO4)3(OH)3·(H2O) P 2₁/c 2/m

VIII/B.29-30 Homilite Ca2(Fe,Mg)B2Si2O10 P 2₁/a 2/m

VIII/B.29-35 Vistepite Mn4SnB2(SiO4)4(OH)2 P1 1

VIII/B.29-40 Minasgeraisite-(Y) CaY2Be2Si2O10 P 2₁/a 2/m

VIII/B.29-50 Gadolinite-(Y) Y2FeBe2Si2O10 P 2₁/a 2/m

VIII/B.29-60 Gadolinite-(Ce) (Ce,La,Nd,Y)2FeBe2Si2O10 P 2₁/c 2/m

VIII/B.29-70 Hingganite-(Y) Y2([])Be2Si2O8(OH)2 P 2₁/a 2/m

VIII/B.29-80 Hingganite-(Ce) Ce2Be2(SiO4)2(OH)2 P 2₁/a 2/m

VIII/B.29-90 Hingganite-(Yb) (Yb,Y)2([])Be2Si2O8(OH)2 P 2₁/a 2/m

VIII/B.29-100 Calcybeborosilite-(Y)! (REE,Ca)2[](B,Be)2(SiO4)2(OH,O)2 P 2₁/a 2/m

Other Homilite Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

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Homilite

Ca2(Fe++,Mg)B2Si2O10
Dana No: 54.2.1b.5 Strunz No: VIII/B.29-30
Locality:

Notes: