Orthojoaquinite-(La)

 IMA-2000-D
Thorium 60.1.1b.5
(Dana Classification Number)
(No Images) 8/E.08-89
(Strunz ID)

Property Data Remarks
Named for: its orthorhombic crystal structure, its Lanthanum content, and its relationship to Joaquinite-Ce
Alternate
    Name(s):
  		•  
    Mineral Class:
    Silicates
      Cyclosilicates, quadruplet rings [Si4O11]-8]
        Joaquinite group,
    Baotite - Orthojoaquinite-(Ce) series
    		 
    Chemical
        Formula:    		 Ba2Na(La,Ce)2Fe+2Ti2Si8O26(OH,O,F) · H2O  
    Chemical
        Composition:
    Barium: (Ba) 19.21%
    Cerium: (Ce) 7.84%
    Fluorine: (F) 0.27%
    Hydrogen: (H) 0.17%
    Iron: (Fe) 4.30%
    Lanthanum: (La) 8.75%
    Manganese: (Mn) 0.38%
    Neodymium: (Nd) 2.02%
    Niobium: (Nb) 1.95%
    Oxygen: (O) 31.01%
    Potassium: (K) 0.27%
    Praeseodymium: (Pr) 0.99%
    Silicon: (Si) 15.72%
    Sodium: (Na) 1.77%
    Titanium: (Ti) 5.36%
    Thorium: (Th) (Trace)
    		by weight
    Molecular
        Weight:    		 1,429.39 daltons (amu)
    Specific
        Radioactivity:

    (All radiation is for a 1 gram, fully aged specimen)

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    439 1.19 × 10-08 0.01 0.63

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Orthorhombic - Dipyramidal
    Axial Ratios: a: 1.0887
    b: 1
    c: 2.3083
    Cell Dimensions: a: 10.539 Å
    b: 9.68 Å
    c: 22.345 Å
    Z: 4
    V: 2,279.58 Å3
    DenCalc: 4.16
    H-M Symbol: 2/m 2/m 2/m
    Space Group: Ccmm
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (1): 2.8 Å (313, 008, 225)
    (0.67): 5.58 Å (004)
    (0.17): 2.95 Å (206)
    (0.13): 1.596 Å (0.0.14, 602)
    (0.105): 2.91 Å (117)
    (0.088): 3 Å (224)
    (0.08): 2.232 Å (0.0.10)
    		 
    Habit:
  • Thin, flaky plates to 1 mm
  • Agregates to 1 cm thick
    		•   
    Cleavage:
    [001] Good
    [010]  
    [100]  
    		 
    Fracture: Brittle  
    Moh's
        Hardness:    		 5 - 5.5  
    Density: 4.1 grams/cm3
    Color: Brown  
    Streak:    
    Luster: Silky  
    Diaphaneity: Transparent  
    Pleochroism:
    (x):  
    (y:)  
    (z:)  

    strong - yellow, green

    		  
    Ultra Violet
        Fluorescence:
    Long Wave:  
    Short Wave:  
    		 
    Magnetism: Non-magnetic  
    Occurance:
  • Occurs in nepheline-sodalite syenite pegmatites
  		•   
    Associated
        Minerals:

    Analcime, Naujakasite, Nepheline, Riebeckite, Sodalite, Steenstrupine-(Ce), Villiaumite

    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Orthojoaquinite-(La)
    Locations:

    Extremely rare

    Orthojoaquinite-(La) Locations
    Notes:

    Radioactive a- and b-particles, g-rays.

    Crystals are probably metamic.