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

  
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 % -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 : [Si₉O₂₇]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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