Clinohumite Mineral Data

Clinohumite Mineral Data

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General Clinohumite Information

Chemical Formula:

(Mg,Fe++)9(SiO4)4(F,OH)2

Composition:

Molecular Weight = 695.05 gm

Magnesium 23.60 % Mg 39.14 % MgO

Iron 18.08 % Fe 23.26 % FeO

Silicon 16.16 % Si 34.58 % SiO₂

Hydrogen 0.07 % H 0.65 % H₂O

Oxygen 37.98 % O

Fluorine 4.10 % F 4.10 % F

- % F -1.73 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg_6.75Fe²⁺_2.25(SiO₄)₄F_1.5(OH)_0.5

Environment:

Commonly interlayered with humite.

IMA Status:

Valid Species (Pre-IMA) 1876

Locality:

Mte. Somma, Vesuvius, Italy. Link to MinDat.org Location Data.

Name Origin:

Named after the mineral humite and the monoclinic crystal form.

Synonym:

Titanclinohumite

Clinohumite Image

Images:

Clinohumite

Comments: Orange-brown glassy crystalline clinohumite.
Location: Kuhi-Lal, Pamir, Gorno-Badahsan, Tadzhikistan. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Clinohumite Crystallography

Axial Ratios:

a:b:c =2.8832:1:2.164

Cell Dimensions:

a = 13.71, b = 4.755, c = 10.29, Z = 2; beta = 100.833° V = 658.86 Den(Calc)= 3.50

Crystal System:

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

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

By Intensity(I/I_o): 1.74(1), 3.7(0.7), 5.02(0.7),

Crystal Structure:

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Ottolini L , Camara F , Bigi S , American Mineralogist , 85 (2000) p.89-102, An investigation of matrix effects in the analysis of fluorine in humite-group, minerals by EMPA, SIMS, and SREF, Sample: Chum HV-41 n.3

View Additional jPOWD Structure files for Clinohumite
[1] [2] [3]

Physical Properties of Clinohumite

Cleavage:

[001] Poor

Color:

Brown, Yellow, White, Orange, Reddish brown.

Density:

3.17 - 3.35, Average = 3.26

Diaphaniety:

Transparent to translucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Hardness:

6 - Orthoclase

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Clinohumite

Gladstone-Dale:

CI meas= -0.045 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.027 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1928,KPDmeas= 0.207,KC= 0.1981

Optical Data:

Biaxial (+), a=1.623-1.702, b=1.636-1.709, g=1.651-1.728, bire=0.0260-0.0280, 2V(Calc)=64-88, 2V(Meas)=52-90. Dispersion weak, r > v.

Pleochroism (x):

brownish yellow or pale golden yellow.

Pleochroism (y):

pale yellow, greenish yellow, or colorless.

Pleochroism (z):

pale yellow or colorless.

Calculated Properties of Clinohumite

Electron Density:

r_electron=3.44 gm/cc
note: r_Clinohumite=3.50 gm/cc.

Fermion Index

Fermion Index = 0.03516
Boson Index = 0.96484

Photoelectric:

PE_Clinohumite= 6.52 barns/electron
U=PE_Clinohumite x r_electron= 22.42 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Clinohumite is Not Radioactive

Clinohumite Classification

Dana Class:

52.3.2d.1 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O

(52.3)with cations in [6] coordination only

(52.3.2d)Humite group (Clinohumite series)

52.3.2d.1 Clinohumite (Mg,Fe)9(SiO4)4(F,OH)2 P 2₁/c 2/m

52.3.2d.2 Jerrygibbsite (Mn,Zn)9(SiO4)4(OH)2 Pbn21 mm2

52.3.2d.3 Sonolite Mn9(SiO4)4(OH,F)2 P 2₁/a 2/m

52.3.2d.4 Hydroxylclinohumite! Mg9(SiO4)4(OH,F)2 P 2₁/c 2/m

Strunz Class:

VIII/B.04-40 VIII - Silicates

VIII/B - Nesosubsilicates, with anions unfamiliar to tetraheders, cations of octahedral and tetrahedral orientation [4/6]

VIII/B.04 - Humite group

VIII/B.04-10 Norbergite Mg3(SiO4)(F,OH)2 P nma 2/m 2/m 2/m

VIII/B.04-20 Chondrodite (Mg,Fe)5(SiO4)2(F,OH)2 P 2₁/c 2/m

VIII/B.04-30 Humite (Mg,Fe)7(SiO4)3(F,OH)2 P nma 2/m 2/m 2/m

VIII/B.04-40 Clinohumite (Mg,Fe)9(SiO4)4(F,OH)2 P 2₁/c 2/m

VIII/B.04-42 Hydroxylclinohumite! Mg9(SiO4)4(OH,F)2 P 2₁/c 2/m

VIII/B.04-50 Ribbeite (Mn,Mg)5(SiO4)2(OH)2 P nma 2/m 2/m 2/m

VIII/B.04-60 Alleghanyite Mn5(SiO4)2(OH)2 P 2₁/a 2/m

VIII/B.04-70 Reinhardbraunsite Ca5(SiO4)2(OH,F)2 P 2₁/a 2/m

VIII/B.04-80 Manganhumite (Mn,Mg)7(SiO4)3(OH)2 Pbnm 2/m 2/m 2/m

VIII/B.04-90 Leucophoenicite Mn7(SiO4)3(OH)2 P 2₁/a 2/m

VIII/B.04-100 Jerrygibbsite (Mn,Zn)9(SiO4)4(OH)2 Pbn21 mm2

VIII/B.04-110 Sonolite Mn9(SiO4)4(OH,F)2 P 2₁/a 2/m

Other Clinohumite Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

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Clinohumite

(Mg,Fe++)9(SiO4)4(F,OH)2
Dana No: 52.3.2d.1 Strunz No: VIII/B.04-40
Locality:

Notes: