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Johnsenite-(Ce) (inclusions in Quartz)
Current inventory: 0 gems
 

Johnsenite-(Ce) inclusions in Quartz

  
Johnsenite-(Ce) was named to honor Ole Johnsen (1940- ), Geological Museum, University of Copenhagen, Denmark, for his research on the Eudialyte Group and the minerals of Greenland. The -(Ce) suffix is added because of the dominant rare earth element, cerium (Ce).

Discovered in 2004; IMA status: Valid (IMA Approved 2004)

 

Chemistry

 

 

Chemical Formula:

Na12(Ce,La,Sr,Ca,)3Ca6Mn3Zr3W(Si25O73)(CO3)(OH,Cl)2

 

Sodium REE Calcium Manganese Zirconium Silicate Carbonate Hydroxide Chloride

Molecular Weight:

3,374.09 gm

Composition:

Potassium

0.22 %

K

0.27 %

K2O

 

Sodium

8.00 %

Na

10.78 %

Na2O

 

Strontium

1.40 %

Sr

1.66 %

SrO

 

Calcium

6.62 %

Ca

9.26 %

CaO

 

Lanthanum

1.36 %

La

1.59 %

La2O3

 

Cerium

2.66 %

Ce

3.11 %

Ce2O3

 

Praeseodymium

1.00 %

Pr

1.17 %

Pr2O3

 

Samarium

0.09 %

Sm

0.10 %

Sm2O3

 

Gadolinium

0.28 %

Gd

0.32 %

Gd2O3

 

Dysprosium

0.14 %

Dy

0.17 %

Dy2O3

 

Yttrium

0.58 %

Y

0.74 %

Y2O3

 

Hafnium

0.05 %

Hf

0.06 %

HfO2

 

Zirconium

7.33 %

Zr

9.90 %

ZrO2

 

Titanium

0.45 %

Ti

0.76 %

TiO2

 

Manganese

4.33 %

Mn

5.59 %

MnO

 

Niobium

0.58 %

Nb

0.83 %

Nb2O5

 

Iron

1.29 %

Fe

1.66 %

FeO

 

Silicon

20.78 %

Si

44.47 %

SiO2

 

Hydrogen

0.04 %

H

0.33 %

H2O

 

Tungsten

4.25 %

W

5.36 %

WO3

 

Carbon

0.36 %

C

1.30 %

CO2

 

Neodymium

0.77 %

Nd

0.90 %

Nd2O3

 

Chlorine

0.79 %

Cl

0.79 %

Cl

 

 —  %

Cl

-0.18 %

-0.18 % -O=Cl2

 

Oxygen

36.63 %

O

 

 

 

 

100.00 %

 

100.94 %

= TOTAL OXIDE

 

 

Classification

   

   

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/E.25-57

Nickel-Strunz 10th Ed. ID:

9.CO.10

 

9 : SILICATES (Germanates)
C : Cyclosilicates
O : [Si
9O27]18- 9-membered rings

Related to:

Eudialyte Group. The tungsten (W) analogue of Zirsilite-(Ce).

Members of Group:

Eudialyte Group: Alluaivite, Andrianovite, Aqualite, Carbokentbrooksite, Davinciite, Dualite, Eudialyte, Feklichevite, Fengchengite, Ferrokentbrooksite, Georgbarsanovite, Golyshevite, Ikranite, Johnsenite-(Ce), Kentbrooksite, Khomyakovite, Labyrinthite, Manganoeudialyte, Manganokhomyakovite, Mogovidite, Oneillite, Raslakite, Rastsvetaevite, Taseqite, UM1998-21-SiO:CaCeClHMnNaZr, Voronkovite, Zirsilite-(Ce)

Varieties:

None

Synonyms:

IMA2004-026

 

 

Crystal Data

   

   

Crystallography:

Trigonal - Ditrigonal Pyramidal

Crystal Habit:

As deeply etched, skeletal crystals, to 4 mm and in aggregates to 1 cm; crystals display partial {0001} and {1011}. 

Twinning:

None

 

 

Physical Properties

   

 

Cleavage:

None

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

5.0 - 6.0

Density:

3.24 (g/cm3)

Luminescence:

None

Radioactivity:

Mild; GRapi = 6,454.67 (Gamma Ray American Petroleum Institute Units)

Health Warning:

Mildly Radioactive - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. Avoid prolonged exposure in proximity of the body. Store away from inhabited areas.

 

 

Optical Properties

   

   

Color:

Pale yellow to bright orange

Transparency:

Transparent to translucent

Luster:

Vitreous

Refractive Index:

1.637 - 1.648  Uniaxial ( - )

Birefringence:

0.011

Dispersion:

n/a

Pleochroism:

n/a

 

 

Occurances

   

   

Geological Setting:

In a cavity near the margin of a marble xenolith in an igneous breccia along the contact between porphyritic nepheline syenite and sodalite syenite in an alkaline igneous complex.

Common Associations:

Albite, Calcite, Pectolite, Aegirine, Fluorapophyllite, Zirsilite-(Ce), a Burbankite Group mineral, Dawsonite, Rhodochrosite, Epididymite, Galena, Molybdenite, Pyrite, Pyrrhotite, Quartz, an Amphibole Group mineral, Sphalerite, Stillwellite-(Ce), Titanite, Cerite-(Ce), Tuperssuatsiaite, Steacyite, Catapleiite, Zakharovite, Natrolite, Microcline

Common Impurities:

None

Type Locality:

Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry; Carrière Mont Saint-Hilaire), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada

Year Discovered:

2004 (IMA Approved 2004)

View mineral photos:

Johnsenite-(Ce) Mineral Photos and Locations

 

 

Unusual Gem Categories

   

   

 

Inclusions in Quartz, Radioactive Gems, Rare Earth Elements (REE) Gems

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Johnsenite-(Ce) is a fairly new mineral species discovered in 2004 at the Poudrette quarry, Mont Saint-Hilaire, Québec, Canada. Johnsenite-(Ce) is a rare cyclosilicate that is also a 
rare earth elements (REE) mineral. It contains eight of the fifteen lanthanide elements: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), gadolinium (Gd), dysprosium (Dy), plus yttrium (Y). It also contains the elements strontium (Sr), hafnium (Hf), zironium (Zr), titanium (Ti), niobium (Nb) and tungsten (W). That's a lot of rare and unusual elements! There are only a few other gems that contain a similar amount of REE and unusual elements; Kentbrooksite, Titanite, Xenotime and Zircon. Johnsenite-(Ce) is also mildly radioactive.

Johnsenite-(Ce) occurrs as yellow to bright orange, deeply etched, skeletal crystals. It is also found as tiny, orange skeletal crystal inclusions in Quartz along with inclusions of reddish brown radiating crystals of MacFallite and black Braunite crystals from the Arthur Costa mine, Jaguaracu, Minas Gerais, Brazil. The picture above shows a faceted Quartz gem with inclusions of an orange skeletal crystal of Johnsenite-(Ce) along with a reddish brown radiating crystal of MacFallite. If you place your cursor over the picture you will see a magnified picture of the orange Johnsenite-(Ce) crystal.

Johnsenite-(Ce) was named to honor Ole Johnsen (1940- ), Geological Museum, University of Copenhagen, Denmark, for his research on the Eudialyte Group and the minerals of Greenland. The -(Ce) suffix is added because of the dominant rare earth element, cerium (Ce).

Johnsenite-(Ce) distribution: from level 7 bench, SE wall, Poudrette Quarry, Mont Saint-Hilaire, Quebec, Canada. As inclusions in Quartz from the Arthur Costa mine, Jaguaracu, Minas Gerais, Brazil.
 

  
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