Tinaksite - Occurrence, Properties, and Distribution

Topics Covered

Introduction to Tinaksite
Properties of Tinaksite
How to Identify Tinaksite
Global Distribution
Occurrence of Tinaksite and Useful Mineral Association
References

Introduction to Tinaksite

Chemical Formula – K2Na(Ca,Mn++)2(Ti,Fe)O[Si7O18(OH)]

Tinaksite was first discovered in 1965 from Murun alkalic massif, near Olekminsk, Yakutia, Russia. It was named after the presence of titanium, sodium, potassium and silicon in its composition.

Properties of Tinaksite

The following are the key properties of tinaksite:

  • Cell Data
    • Space Group: P1
    • a = 10.377(3)
    • b = 12.166(3)
    • c = 7.059(1)
    • α = 90:91(1)°
    • β = 99:3(1)°
    • γ = 92:76(3)°
    • Z = 2
  • Crystal Data
    • Triclinic
    • Point Group: 1
    • As well-formed long prismatic crystals, to 15 cm; commonly as bundles and rosettes of radiating crystals, or compact fibrous aggregates, to 10 cm
    • X-ray Powder Pattern: 3.03 (100), 3.25 (80), 2.331 (55), 3.09 (50), 2.952 (50), 2.865 (50), 2.674 (45)
  • Chemical Composition
    Elements Content 1
    SiO2 55.82
    CaO 14.20
    K2O 12.55
    TiO2 10.12
    Na2O 4.30
    H2O+ 1.20
    FeO 0.92
    Fe2O3 0.91
    MnO 0.40
    H2O- 0.08
    MgO 0.04
    Al2O3 trace
    Total 100.54
  • Optical Properties
    • Optical Class: Biaxial (+)
    • Pleochroism: X = Y = colorless; Z = pale orange-brown.
    • Orientation: X’ ^ {010} = 1°- 4°; Y ^ {010} = 16°-18°
    • Dispersion: Strong
    • α = 1.593-1.599
    • β = 1.621-1.627
    • γ = 1.666-1.673
    • 2V(meas.) = 68°-78°
  • Estimated Properties
    Electron density Bulk density (electron density)=2.79 g/cm3
    note: Specific gravity of Tinaksite =2.82 g/cm3
    Photoelectric PETinaksite = 4.91 barns/electron
    U= PETinaksite x ρElectron density= 13.70 barns/cm3
    Fermion index Fermion index = 0.01
    Boson index = 0.99
    Radioactivity

    Tinaksite is barely detectable

How to Identify Tinaksite

Tinaksite occurs in light brown, pale yellow or pink color. It has a perfect cleavage, transparent to translucent appearance, vitreous luster and white streak. It can be formed as prismatic, fibrous or radial crystals. The mineral has a relative hardness of 6 and density of 2.82 g/cm3.

Global Distribution

Tinaksite is distributed in the following places:

  • Murun massif, southwest of Olekminsk, Yakutia, Russia
  • Mt. Rasvumchorr, Khibiny massif, Kola Peninsula.

Occurrence of Tinaksite and Useful Mineral Association

Tinaksite occurs as an accessory mineral in potassic feldspar metasomatites at the contact with limestones. It is closely associated with hisingerite, astrophyllite, aegirine, pyroxene, orthoclase, xonotlite, canasite, quartz, and potassic feldspar.

References


Date Added: Mar 28, 2013 | Updated: Jun 11, 2013
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