Rondorfite

Caspar quarry, Ettringer Bellerberg Mt. (Bellberg Mt.; Bellenberg Mt.; Billenberg Mt.; Boilenberg Mt.), Bellerberg volcano, Ettringen, Mayen, Eifel Mts, Rhineland-Palatinate, Germany
© Elmar Lackner

Show Rondorfite Photos (5)

Formula:

Mg[Cl

|(SiO

)

]

System:

Isometric

Colour:

orange brown to amber

Name:

for the collectors Alice and Eugen Rondorf, who discovered the mineral

This page provides mineralogical data about Rondorfite.

Classification of Rondorfite

IMA status:

Approved 1997

Strunz 8th edition ID:

8/B.05-05

Nickel-Strunz 10th (pending) edition ID:

9.AB.20

9 : SILICATES (Germanates)
A : Nesosilicates
B : Nesosilicates without additional anions; cations in [4] and greater coordination

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http://www.mindat.org/min-25682.html
Please feel free to link to this page.

Type Occurrence of Rondorfite

Type Locality:

Caspar quarry, Ettringer Bellerberg Mt. (Bellberg Mt.; Bellenberg Mt.; Billenberg Mt.; Boilenberg Mt.), Bellerberg volcano, Ettringen, Mayen, Eifel Mts, Rhineland-Palatinate, Germany

General Appearance of Type Material:

minute grains to 0.5 mm

Year of Discovery:

1979

Geological Setting of type material:

thermally altered calcium-rich xenolites in rocks contacting leucite-rich lava slags

Associated Minerals at type locality:

Tobermorite	Thaumasite	Ternesite	Quartz	Portlandite
Olivine	Mayenite	Magnetite	Larnite	Hydrocalumite
Hematite	Ettringite	Ellestadite	Cuspidine

Physical Properties of Rondorfite

Lustre:

Vitreous

Diaphaneity (Transparency):

Translucent

Colour:

orange brown to amber

Streak:

pale yellow

Tenacity:

Brittle

Cleavage:

None Observed

Fracture:

Conchoidal

Density (measured):

3.03 g/cm³

Crystallography of Rondorfite

Crystal System:

Isometric

Class (H-M):

m3 (2/m 3) - Diploidal

Cell Parameters:

a = 15.08Å

Unit Cell Volume:

V 3,429.29 Å³ (Calculated from Unit Cell)

X-Ray Powder Diffraction:

d-spacing		Intensity
2.90		(40)
2.66		(100)

Chemical Properties of Rondorfite

Formula:

Mg[Cl

|(SiO

)

]

All elements listed in formula:

Ca, Cl, Mg, O, Si

Relationship of Rondorfite to other Species

9.AB.05

Trimerite

CaMn

[SiO

]

9.AB.10

Larsenite

PbZn[SiO

]

9.AB.15

Esperite

PbCa

[SiO

]

Other Names for Rondorfite

Synonyms:

IMA1997-013

Other Languages:

German:	Rondorfit

Other Information

Fluorescence in UV light:

none

Health Warning:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Rondorfite

Reference List:

Mihajlović, T., C. L. Lengauer, T. Ntaflos, U. Kolitsch and E. Tillmanns (2004): Two new minerals rondorfite, Ca8Mg[SiO4]4Cl2, and almarudite, K(ٱ,Na)2(Mn,Fe,Mg)2(Be,Al)3[Si12O30], and a study of iron-rich wadalite, Ca12[(Al8Si4Fe2)O32]Cl6, from the Bellerberg (Bellberg) volcano, Eifel, Germany. Neues Jahrbuch für Mineralogie, Abhandlungen: 179: 265-294.

Rastsvetaeva, R.K., A. E. Zadov, N.V. Chukanov (2008) Crystal structure of low-symmetry rondorfite. Kristallografiya, 2008, Vol. 53, No. 2, pp. 226–232.