Rhonite Mineral Data

Rhonite Mineral Data +

General Rhonite Information

Chemical Formula:

Ca2(Mg,Fe++,Fe+++,Ti)6(Si,Al)6O20

Composition:

Molecular Weight = 814.43 gm

Potassium 0.48 % K 0.58 % K₂O

Sodium 0.56 % Na 0.76 % Na₂O

Calcium 8.86 % Ca 12.39 % CaO

Magnesium 7.46 % Mg 12.37 % MgO

Titanium 5.88 % Ti 9.81 % TiO₂

Aluminum 8.94 % Al 16.90 % Al₂O₃

Iron 17.14 % Fe 11.47 % FeO / 11.76 % Fe₂O₃

Silicon 11.38 % Si 24.35 % SiO₂

Oxygen 39.29 % O

______ ______

100.00 % 100.39 % = TOTAL OXIDE

Empirical Formula:

Ca_1.8Na_0.2K_0.1Mg_2.5Fe²⁺_1.3Fe³⁺_1.2TiSi_3.3Al_2.7O₂₀

Environment:

In silica-undersaturated, alkalic, mafic to intermediate igneous rocks, as a primary mineral or alteration of amphiboles.

IMA Status:

Valid Species (Pre-IMA) 1907

Locality:

Rhon Mountains, at Scharnhausen, near Stuttgart, Germany. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Synonym:

Rhoenite

Rhonite Image

Images:

Rhonite

Comments: Brown, striated, tabular crystal of rhonite on matrix.
Location: Sattleberg, Laacher See, Rhineland-Pal., Germany. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Rhonite Crystallography

Axial Ratios:

a:b:c =0.9592:1:0.8395

Cell Dimensions:

a = 10.478, b = 10.923, c = 9.17, Z = 2; alpha = 101.43°, beta = 96.95°, gamma = 129.68° V = 785.90 Den(Calc)= 3.44

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 2.947(1), 2.55(0.7), 2.691(0.65),

Crystal Structure:

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Bonaccorsi E , Merlino S , Pasero M , European Journal of Mineralogy , 2 (1990) p.203-218, Rhonite: structural and microstructural features, crystal, chemistry and polysomatic relationships, Locality: volcanic breccias of Scharnhausen

View Additional jPOWD Structure files for Rhonite
[1]

Physical Properties of Rhonite

Cleavage:

[010] Good, [001] Good

Color:

Brown.

Density:

3.4 - 3.76, Average = 3.58

Diaphaniety:

Subtranslucent to Opaque

Habit:

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

Habit:

Skeletal - Crystals form crude outlines with missing faces.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Sub Metallic

Optical Properties of Rhonite

Optical Data:

Biaxial (+), a=1.795-1.81, b=1.806-1.825, g=1.83-1.845, bire=0.0350, 2V(Calc)=70-84, 2V(Meas)=50-90. Dispersion r > v extreme.

Pleochroism (x):

dark greenish brown or red brown.

Pleochroism (y):

dark reddish brown or dark greenish brown.

Pleochroism (z):

dark reddish brown or black.

Calculated Properties of Rhonite

Electron Density:

r_electron=3.37 gm/cc
note: r_Rhonite=3.44 gm/cc.

Fermion Index

Fermion Index = 0.02431
Boson Index = 0.97569

Photoelectric:

PE_Rhonite= 8.09 barns/electron
U=PE_Rhonite x r_electron= 27.21 barns/cc.

Radioactivity:

GRapi = 6.76 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Rhonite - barely detectable

Rhonite Classification

Dana Class:

69.2.1a.5 (69)Inosilicate Chains with Side Branches or Loops

(69.2)with P>2

(69.2.1a)Aenigmatite and related species (Aenigmatite subgroup)

69.2.1a.1 Aenigmatite Na2Fe5TiSi6O20 P1 1

69.2.1a.2 Dorrite Ca2Mg2Fe4(Al,Fe)4Si2O20 P1,P 1 Tri

69.2.1a.3 Hogtuvaite (Ca,Na)2(Fe,Fe,Ti,Mg,Mn)6(Si,Be,Al)6O20 P1 1

69.2.1a.4 Krinovite NaMg2CrSi3O10 P1 1

69.2.1a.5 Rhonite Ca2(Mg,Fe,Fe,Ti)6(Si,Al)6O20 P1 1

69.2.1a.6 Serendibite Ca2(Mg,Al)6(Si,Al,B)6O20 P1 1

69.2.1a.7 Welshite Ca2Mg4(Mn,Fe)Sb2O2[Si3Be2O18] P1 1

69.2.1a.8 Wilkinsonite Na2Fe4Fe2Si6O20 P1 1

69.2.1a.9 IMA2002-009a! Ca2Fe4FeTiSi4BeAlO20 P1 1

Strunz Class:

VIII/F.14-50 VIII - Silicates

VIII/F - Inosilicates (chain and band) modified double chains

VIII/F.14 - Aenigmatite group

VIII/F.14-10 Krinovite NaMg2CrSi3O10 P1 1

VIII/F.14-20 Aenigmatite Na2Fe5TiSi6O20 P1 1

VIII/F.14-30 Wilkinsonite Na2Fe4Fe2Si6O20 P1 1

VIII/F.14-35 Hogtuvaite (Ca,Na)2(Fe,Fe,Ti,Mg,Mn)6(Si,Be,Al)6O20 P1 1

VIII/F.14-40 Dorrite Ca2Mg2Fe4(Al,Fe)4Si2O20 P1,P 1 Tri

VIII/F.14-50 Rhonite Ca2(Mg,Fe,Fe,Ti)6(Si,Al)6O20 P1 1

VIII/F.14-60 Serendibite Ca2(Mg,Al)6(Si,Al,B)6O20 P1 1

VIII/F.14-70 Welshite Ca2Mg4(Mn,Fe)Sb2O2[Si3Be2O18] P1 1

Other Rhonite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(AntBidBlaNic2) OPTIC PROP.(AntBidBlaNic2)

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Rhonite

Ca2(Mg,Fe++,Fe+++,Ti)6(Si,Al)6O20
Dana No: 69.2.1a.5 Strunz No: VIII/F.14-50
Locality:

Notes: