Rondorfite Mineral Data

General Rondorfite Information

Chemical Formula:

Ca8Mg(SiO4)4Cl2

Composition:

Molecular Weight = 782.89 gm

Sodium 0.06 % Na 0.08 % Na₂O

Calcium 41.41 % Ca 57.95 % CaO

Magnesium 2.76 % Mg 4.58 % MgO

Titanium 0.06 % Ti 0.10 % TiO₂

Aluminum 0.21 % Al 0.39 % Al₂O₃

Iron 0.43 % Fe 0.55 % FeO

Silicon 14.49 % Si 31.01 % SiO₂

Hydrogen 0.04 % H 0.33 % H₂O

Chlorine 6.84 % Cl 6.84 % Cl

- % Cl -1.54 % -O=Cl₂

Oxygen 33.70 % O

______ ______

100.00 % 100.29 % = TOTAL OXIDE

Empirical Formula:

Ca_8.09Na_0.02Mg_0.89Al_0.06Fe²⁺_0.06Si_4.04Ti_0.01O_16.2Cl_1.51(OH)_0.29

Environment:

In xenoliths in leucite tephrite lava.

IMA Status:

Approved IMA 1997 (Dana # Added)

Locality:

A quarry at the Bellerberg volcano lava field, near Ettringen, 2 km north of Mayen, Laacher See region, eastern Eifel area, Germany. Link to MinDat.org Location Data.

Name Origin:

Named for Alice and Eugen Rondorf, two distinguished mineral collectors, who found the mineral with Bernd Ternes in 1979.

Synonym:

IMA1997-013

Rondorfite Image

Images:

Rondorfite

Comments: Brown to orange, shiny, massive rondorfite in matrix.
Location: Bellerberg, Eifel, Germany. Scale: Not Given.
© Diederik Visser

Images:

Rondorfite Kumtyubeite Srebrodolskite Wadalite

Comments: BSE image of kumtyubeite (Kmt) associated with srebrodolskite (Srb), bultfonteinite (Blt), Ca- kydrosilicates, wadalite (Wad), rondorfite (Rndr), and ettringite (dark gray). (AmMin, v94:1361).
Location: Rock-forming mineral found in skarn carbonate-xenoliths in ignimbrites of the Upper Chegem volcanic structure, Kabardino-Balkaria, Northern Caucasus, Russia. Scale: See Image.
© American Mineralogist

Rondorfite Crystallography

Cell Dimensions:

a = 15.085, Z = 8; V = 3,432.70 Den(Calc)= 3.03

Crystal System:

Isometric - DiploidalH-M Symbol (2/m 3) Space Group: F d3

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

By Intensity(I/I_o): 2.666(1)(440), 1.54(0.5)(844), 2.901(0.4)(511),1.4959(0.3)(951), 1.777(0.3)(822), 1.885(0.3)(800), 1.964(0.3)(553),

Crystal Structure:

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Rastsvetaeva R K , Zadov A E , Chukanov N V , Crystallography Reports , 53 (2008) p.199-205, Crystal structure of low-symmetry rondorfite, Locality: Kabardino-Balkarian Republic, Northern Caucasus Region, Russia

Physical Properties of Rondorfite

Color:

Orange brown, Amber brown.

Diaphaneity:

Transparent

Fracture:

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

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Luster:

Vitreous (Glassy)

Streak:

light amber

Optical Properties of Rondorfite

Gladstone-Dale:

CI calc= -0.003 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2211,KC= 0.2205
Ncalc = 1.67

Optical Data:

Isotropic, n=1.67.

Calculated Properties of Rondorfite

Electron Density:

Bulk Density (Electron Density)=3.02 gm/cc
note: Specific Gravity of Rondorfite =3.03 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Rondorfite= 6.28 barns/electron
U=PE_Rondorfite x rElectron Density= 18.95 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Rondorfite is Not Radioactive

Rondorfite Classification

Dana Class:

51.04.06.01 (51)Nesosilicate Insular SiO4 Groups Only

(51.04)with cations in [6] and >[6] coordination

(51.04.06)Dana Group

51.04.06.01 Rondorfite! Ca8Mg(SiO4)4Cl2 F d3 2/m 3

Strunz Class:

09.AB.20 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AB -Nesosilicates without additional anions;

09.AB.20 Rondorfite! Ca8Mg(SiO4)4Cl2 F d3 2/m 3

Other Rondorfite Information

References:

NAME( CanMin, 42:1283) PHYS. PROP.(CanMin, 42:1283) OPTIC PROP.(CanMin, 42:1283)

See Also:

Links to other databases for Rondorfite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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

Rondorfite

Ca8Mg(SiO4)4Cl2
Dana No: 51.04.06.01 Strunz No: 09.AB.20
Locality:

Notes: