Alleghanyite Mineral Data

Alleghanyite Mineral Data +

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General Alleghanyite Information

Chemical Formula:

Mn5(SiO4)2(OH)2

Composition:

Molecular Weight = 492.87 gm

Manganese 55.73 % Mn 71.96 % MnO

Silicon 11.40 % Si 24.38 % SiO₂

Hydrogen 0.41 % H 3.66 % H₂O

Oxygen 32.46 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺₅(SiO₄)₂(OH)₂

Environment:

Manganese vein deposits.

IMA Status:

Valid Species (Pre-IMA) 1932

Locality:

Bald Knob, Alleghany Co., North Carolina, USA. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Synonym:

ICSD 14253

PDF 43-683

Alleghanyite Image

Images:

Alleghanyite

Comments: Massive, brown alleghanyite with white calcite.
Location: Parker Shaft, Franklin, Sussex County, New Jersey. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Alleghanyite Galaxite

Comments: Black granular galaxite with reddish alleghanyite and white kutnohorite.
Location: Bald Knob, Alleghany County, North Carolina, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Alleghanyite Crystallography

Axial Ratios:

a:b:c =2.1522:1:1.7078

Cell Dimensions:

a = 10.46, b = 4.86, c = 8.3, Z = 2; beta = 109.133° V = 398.63 Den(Calc)= 4.11

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): 1.799(1), 2.86(0.8), 2.598(0.6),

Crystal Structure:

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Francis C A , American Mineralogist , 70 (1985) p.182-185, Crystal structure refinement of magnesian alleghanyite

Physical Properties of Alleghanyite

Cleavage:

None

Color:

White, Brown, Bright pink, Grayish pink.

Density:

Diaphaniety:

Transparent to Subtransparent to translucent

Fracture:

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

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Massive - Lamellar - Distinctly foliated fine-grained forms.

Hardness:

6-5

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Optical Properties of Alleghanyite

Gladstone-Dale:

CI meas= 0.053 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.079 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1888,KPDmeas= 0.194,KC= 0.2049

Optical Data:

Biaxial (-), a=1.756, b=1.78, g=1.792, bire=0.0360, 2V(Calc)=68, 2V(Meas)=72. Dispersion r > v.

Calculated Properties of Alleghanyite

Electron Density:

r_electron=3.81 gm/cc
note: r_Alleghanyite=4.00 gm/cc.

Fermion Index

Fermion Index = 0.00547
Boson Index = 0.99453

Photoelectric:

PE_Alleghanyite= 14.88 barns/electron
U=PE_Alleghanyite x r_electron= 56.77 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Alleghanyite is Not Radioactive

Alleghanyite Classification

Dana Class:

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

(52.3)with cations in [6] coordination only

(52.3.2b)Humite group (Chondrodite series)

52.3.2b.1 Alleghanyite Mn5(SiO4)2(OH)2 P 2₁/a 2/m

52.3.2b.2 Chondrodite (Mg,Fe)5(SiO4)2(F,OH)2 P 2₁/c 2/m

52.3.2b.3 Reinhardbraunsite Ca5(SiO4)2(OH,F)2 P 2₁/a 2/m

52.3.2b.4 Ribbeite (Mn,Mg)5(SiO4)2(OH)2 P nma 2/m 2/m 2/m

Strunz Class:

VIII/B.04-60 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 Alleghanyite Information

References:

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

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

Alleghanyite

Mn5(SiO4)2(OH)2
Dana No: 52.3.2b.1 Strunz No: VIII/B.04-60
Locality:

Notes: