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| 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) |
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Chemistry
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Chemical
Formula: |
Na12(Ce,La,Sr,Ca,)3Ca6Mn3Zr3W(Si25O73)(CO3)(OH,Cl)2
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Sodium REE
Calcium Manganese Zirconium Silicate Carbonate Hydroxide Chloride
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Molecular
Weight: |
3,374.09 gm
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Composition: |
Potassium |
0.22 % |
K |
0.27 % |
K2O |
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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 |
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Cerium |
2.66 % |
Ce |
3.11 % |
Ce2O3 |
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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 |
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Hafnium |
0.05 % |
Hf |
0.06 % |
HfO2 |
|
Zirconium |
7.33 % |
Zr |
9.90 % |
ZrO2 |
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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 |
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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 |
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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 |
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Classification
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Mineral
Classification: |
Silicates (Germanates)
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Strunz 8th
Ed. ID:
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8/E.25-57
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Nickel-Strunz 10th
Ed. ID:
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9.CO.10
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9 : SILICATES (Germanates)
C : Cyclosilicates O : [Si9O27]18- 9-membered rings
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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)
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Varieties: |
None
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Synonyms: |
IMA2004-026
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Crystal
Data
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Crystallography:
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Trigonal - Ditrigonal Pyramidal
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Crystal
Habit:
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As
deeply etched, skeletal crystals, to 4 mm and in aggregates
to 1 cm; crystals display partial {0001} and {1011}.
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Twinning:
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None
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Physical
Properties
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Cleavage: |
None
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Fracture: |
Irregular/Uneven
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Tenacity:
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Brittle
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Moh's
Hardness: |
5.0
- 6.0
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Density:
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3.24 (g/cm3)
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Luminescence:
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None
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Radioactivity:
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Mild;
GRapi = 6,454.67 (Gamma Ray American Petroleum Institute Units)
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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. |
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Optical
Properties
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Color: |
Pale
yellow to bright orange
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Transparency: |
Transparent to
translucent |
Luster: |
Vitreous |
Refractive
Index: |
1.637
- 1.648 Uniaxial ( - )
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Birefringence: |
0.011
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Dispersion: |
n/a |
Pleochroism: |
n/a |
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Occurances
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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
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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 |
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Unusual
Gem Categories
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Inclusions
in Quartz, Radioactive
Gems,
Rare
Earth Elements (REE)
Gems |
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More
Information
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Mindat.org
Webmineral.com
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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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