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Almarudite

Big Photo

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

Show Almarudite Photos (3)
Formula:
K([],Na)
 
2
(Mn
2+
 
,Fe
2+
 
,Mg)
 
2
(Be,Al)
 
3
[Si
 
12
O
 
30
]
System:HexagonalColour:yellow to orange
Hardness:6
Name:For the University of Vienna, Austria (in latin: ALma MAter RUDolphina)


Osumilite Group.
Calcium- and water-free analogue of milarite.

Can be distinguished from its Mg analogue friedrichbeckeite and yellowish roedderite only by quantitative chemical analysis.

Classification of Almarudite

IMA status:Approved 2002
Strunz 8th edition ID:8/E.22-22
Nickel-Strunz 10th (pending) edition ID:9.CM.05

9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
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Type Occurrence of Almarudite

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:tabular crystals to 1.5 mm across
Year of Discovery:1982
Geological Setting of type material:in vugs of siliceous xenolites in leucite-rich lava slags
Associated Minerals at type locality:
TridymiteSillimaniteSanidineQuartzHematite
Clinopyroxene SubgroupBrauniteAmphibole Group

Physical Properties of Almarudite

Lustre:Vitreous
Diaphaneity (Transparency):Transparent, Translucent
Colour:yellow to orange
Streak:pale orange
Hardness (Mohs):6
Tenacity:Brittle
Cleavage:None Observed
Fracture:Irregular/Uneven
Density (measured):2.71 g/cm3

Crystallography of Almarudite

Crystal System:Hexagonal
Class (H-M):6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:P6/mmm {P6m 2/m 2/m}
Cell Parameters:a = 9.99Å, c = 14.09Å
Ratio:a:c = 1 : 1.41
Unit Cell Volume:V 1,217.79 ų (Calculated from Unit Cell)
Morphology:{0001}, {10_10}, {10_12}, {11_20}
X-Ray Powder Diffraction:
d-spacingIntensity
4.07 (80)
3.18 (90)

Chemical Properties of Almarudite

Formula:
K([],Na)
 
2
(Mn
2+
 
,Fe
2+
 
,Mg)
 
2
(Be,Al)
 
3
[Si
 
12
O
 
30
]
Essential elements:Be, K, Mn, O, Si
All elements listed in formula:Al, Be, Fe, K, Mg, Mn, Na, O, Si

Relationship of Almarudite to other Species

Member of Group:
Osumilite Group:
Related Minerals - Nickel-Strunz Grouping):

- +
9.CM.05Armenite
BaCa
 
2
Al
 
6
Si
 
9
O
 
30
·2H
 
2
O
9.CM.05Brannockite
(K,Na)Li
 
3
Sn
 
2
Si
 
12
O
 
30
9.CM.05Chayesite
K(Mg,Fe)
 
4
FeSi
 
12
O
 
30
9.CM.05Darapiosite
KNa
 
2
Li(Mn,Zn)
 
2
ZrSi
 
12
O
 
30
9.CM.05Eifelite
KNa
 
3
Mg
 
4
Si
 
12
O
 
30
9.CM.05Merrihueite
(K,Na)
 
2
(Fe,Mg)
 
5
Si
 
12
O
 
30
9.CM.05Milarite
K
 
2
Ca
 
4
Al
 
2
Be
 
4
Si
 
24
O
 
60
·H
 
2
O
9.CM.05Osumilite-(Mg)
(K,Na)(Mg,Fe)
 
2
(Al,Fe)
 
3
(Si,Al)
 
12
O
 
30
·H
 
2
O
9.CM.05Osumilite
(K,Na)(Fe
2+
 
,Mg)
 
2
(Al,Fe
3+
 
)
 
3
(Si,Al)
 
12
O
 
30
9.CM.05Poudretteite
KNa
 
2
B
 
3
Si
 
12
O
 
30
9.CM.05Roedderite
(Na,K)
 
2
(Mg,Fe)
 
5
Si
 
12
O
 
30
9.CM.05Sogdianite
(K,Na)
 
2
(Li,Fe)
 
3
(Zr,Ti,Fe)Si
 
12
O
 
30
9.CM.05Sugilite
KNa
 
2
(Fe,Mn,Al)
 
2
Li
 
3
Si
 
12
O
 
30
9.CM.05Yagiite
(Na,K)
 
3
Mg
 
4
(Al,Mg)
 
6
(Si,Al)
 
24
O
 
60
9.CM.05Berezanskite
KLi
 
3
Ti
 
2
Si
 
12
O
 
30
9.CM.05Dusmatovite
K(K,Na,[ ])(Mn
2+
 
,Y,Zr)
 
2
(Zn,Li)
 
3
Si
 
12
O
 
30
9.CM.05Shibkovite
K(Ca,Mn,Na)
 
2
(K
 
2-x
,□
 
x
)
 
2
Zn
 
3
Si
 
12
O
 
30
9.CM.05Trattnerite
([],K)(Mg, Fe
2+
 
)
 
3
Fe
3+
2
[Si
 
12
O
 
30
]
9.CM.05Oftedalite
(Sc,Ca,Mn
2+
 
)
 
2
K[(Be,Al)
 
3
Si
 
12
O
 
30
]
9.CM.10Faizievite
K
 
2
Na(Ca
 
6
Na)Ti
 
4
Li
 
6
[F
 
2
|Si
 
24
O
 
66
]

Other Names for Almarudite

Synonyms:
IMA2002-048
Other Languages:
German:Almarudit

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 Almarudite

Reference List:Mihajlovic, T., Lengauer, C.L., Ntaflos, Th., Kolitsch, U., Tillmanns, E. (2004): Two new minerals, rondorfite, Ca8Mg[SiO4]4Cl2, and almarudite, K(,Na,)2(Mn,Fe,Mg)2(Be,Al)3[Si12O30], and a study of iron-rich wadalite, Ca12[(Al8Si4Fe2)O32]Cl6, from the Bellerberg volcano, Eifel, Germany, N. Jb. Miner. Abh. 179, 265-294.

Lapis 29(3), 39 (2004)

Rondorf, A. & Rondorf, E. (2008): Almarudit vom Bellerberg/Eifel. Mineralien-Welt 19 (5), 4.

Internet Links for Almarudite

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    Localities for Almarudite

    Hide Locality List
    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Germany
     
    • Rhineland-Palatinate
      • Eifel Mts
        • Mayen
          • Ettringen
            • Bellerberg volcano
              • Ettringer Bellerberg Mt. (Bellberg Mt.; Bellenberg Mt.; Billenberg Mt.; Boilenberg Mt.)
    		T. Mihajlovic et al.: N. Jb. Mineral. 179:265-294 (2004); Rondorf, A. & Rondorf, E. (2008): Almarudit vom Bellerberg/Eifel. Mineralien-Welt 19 (5), 4.
    Mineral and/or Locality
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    Copyright © Jolyon Ralph and Ida Chau 1993-2009. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register. Current server date and time: 31st Oct 2009 09:05:37