Eylettersite

 IMA-A 1969-035
Thorium 41.5.12.2
(Dana Classification Number)
(No Images) 7/B.36-100
(Strunz ID)

Property Data Remarks
Named for: Mme. Van Wambeke (née Lea Eyletters), wife of L. van Wambeke, Belgian geologist, who discovered the mineral species
Alternate
    Name(s):
  		•  
    Mineral Class:
    Phosphates, Arsenates and Vanadates
      Waterfree phosphates with unfamiliar anions F, Cl, O, OH.
    Cations of medium and big size: Mg, Cu, Zn, and Ca, Na, K, Ba, Pb
        Crandallite group
    		 
    Chemical
        Formula:    		 (Th,Pb)1-xAl3(PO4,SiO4)2(OH)6  
    Chemical
        Composition:
    Aluminum: (Al) 20.19%
    Hydrogen: (H) 1.70%
    Lead: (Pb) 4.31%
    Oxygen: (O) 45.56%
    Phosphorus: (P) 8.37%
    Silicon: (Si) 0.58%
    Thorium: (Th) 19.29%
    		by weight
    Molecular
        Weight:    		 481.10 daltons (amu)
    Specific
        Radioactivity:

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

    Specific Activity Dose Rate
    Becquerels Curies milliRems/hour microSieverts/hour
    8.643 × 1003 2.34 × 10-07 0.13 12.92

    Estimated Average Annual Exposure: 360 mRem (3.6 milliSieverts)
    Crystalography:
    System: Trigonal - Hexagonal Scalenohedral
    Axial Ratios: a: 1
    c: 2.38912
    Cell Dimensions: a: 6.99 Å
    c: 16.7 Å
    Z: 3
    V: 706.65 Å3
    DenCalc: 3.39
    H-M Symbol: -3 2/m
    Space Group: R-3m
    X-Ray Diffraction:
      By Intensity ( I/Io )    		 (1): 2.95 Å
    (0.6): 3.51 Å
    (0.55): 5.7 Å
    		 
    Habit:
  • Pulverulent
  • Nodular
    		•   
    Cleavage: None  
    Fracture:    
    Moh's
        Hardness:    		 3 - 4  
    Density: 3.38 - 3.44 grams/cm3
    Color: Cream-white  
    Streak: White  
    Luster: Vitreous  
    Diaphaneity: Transparent to Translucent  
    Pleochroism:
    (x):  
    (y:)  
    (z:)  
    		 
    Ultra Violet
        Fluorescence:
    Long Wave: weak Cream brown
    Short Wave: Greenish yellow
    		 
    Magnetism: Non-magnetic  
    Occurance:
  • Alteration product of thorian crandallite in a phosphate-rich granite pegmatite
    		•   
    Associated
        Minerals:

    Althupite, Amblygonite, Beryl, Columbite', Dumontite, Eylettersite, Furongite, Kamitugaite, Lusungite, Meta-Autunite, Metavanmeersscheite, Montebrasite, 'Moreauite', Mundite, Phosphuranylite, Phuralumite, Plumbomicrolite, Quartz, Ranunculite, Rutherfordine, Saléeite, Studtite, Threadgoldite, Triangulite, Upalite, Uraninite, Vanmeersscheite

    Minerals   -   Uranium & Thorium
    mineral links

    		These are minerals known to be found with Eylettersite
    Localities:

    Extremely rare

    Eylettersite Localities
    Notes:

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

    Crystals are probably metamic.