Franklinphilite - Occurrence, Properties, and Distribution

Franklinphilite is a triclinic mineral containing zinc, sodium, silicon, potassium, oxygen, manganese, magnesium, iron, hydrogen and aluminum. It was named after ‘Franklin’, its place of occurrence and ‘philos’, the Greek word for friend. The ‘friends of Franklin’ are the scientists who studied the mineralogy and geology of this deposit.

Properties of Franklinphilite

The following are the key properties of Franklinphilite:

  • Cell Data
    • Space Group: P1 or P1
    • a = 5.521(4)
    • b = 9.560(6)
    • c = 36.57(5)
    • Z = 3/8
  • Crystal Data
    • Triclinic, pseudohexagonal
    • Point Group: 1 or 1
    • Platy crystals, to 0.5 mm, in very fine-grained tangled radial aggregates
    • X-ray Powder Pattern: 12.3 (100), 2.583 (40), 2.737 (30), 2.362 (30), 1.594 (30), 1.580 (30), 4.79 (20)
  • Chemical Composition
    Elements Content
    SiO2 44.0
    MnO 22.3
    H2O 8.1
    Fe2O3 7.8
    MgO 6.4
    ZnO 5.9
    Al2O3 3.6
    K2O 1.5
    Na2O 0.4
    Total [100.0]
  • Optical Properties
    • Optical Class: Biaxial (-)
    • Pleochroism: Distinct
    • X = pale yellow
    • Y = Z = deep brown
    • Orientation: X ^ (001) ˜ 6°
    • α = 1.545(5)
    • β = 1.583(3)
    • γ = 1.583(3)
    • 2V(meas.) = 10(3)°
    • 2V(calc.) = 0°
  • Estimated Properties
    Electron density Bulk density (electron density)=2.60 g/cm3
    note: Specific gravity of Franklinphilite =2.65 g/cm3
    Photoelectric PEFranklinphilite = 9.46 barns/electron
    U= PEFranklinphilite x ρElectron density= 24.61 barns/cm3
    Fermion index Fermion index = 0.01
    Boson index = 0.99
    Radioactivity
    Franklinphilite is barely detectable

How to Identify Franklinphilite

Franklinphilite can be identified by its black or dark brown color. It features light brown streak, vitreous luster, non-fluorescent luminescence and perfect cleavage. It has subtransparent to opaque appearance. Its fractures are brittle as shown by non-metallic minerals and glasses. It exhibits platy form or radial crystal form. The average density of franklinphilite is 2.7 g/cm3, and its relative hardness is 4.

Global Distribution

Franklinphilite is widely distributed at Franklin, Sussex Co., New Jersey, USA.

Occurrence of Franklinphilite and Useful Mineral Association

Franklinphilite occurs in a veinlet crosscutting serpentine, aegirine and a breccia of calcite in a metamorphosed stratiform zinc deposit. The minerals that are closely associated with franklinphilite include tirodite, rhodonite, nelenite and friedelite.

References

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