Editorial Feature

Adamsite - (y) – Occurrence, Properties, and Distribution

Adamsite-(y) was named after Frank Dawson Adams, a professor of geology at the McGill University. This mineral has a Mohs scale rating of 3.

Properties of Adamsite-(y)

The following are the key properties of adamsite-(y):

  • Cell Data
    • Space group: P1
    • a = 6.2592(4)
    • b = 13.0838(7)
    • c = 13.2271(5)
    • α = 91.130(1)°
    • β = 103.554(1)°
    • γ = 90.188(1)°
    • Z = 4

  • Crystal Data
    • Triclinic, pseudo-orthorhombic if twinned
    • Point group: 1
    • Acicular to fibrous, to 2.5cm
    • Elongated along [001], flattened on {001}, showing {010} and {001};
    • Spherical radiating groups, which rarely are reticulated
    • Twinning: By reflection on {001}, common
    • X-ray powder pattern: 12.81 (100), 6.45 (70), 4.456 (60), 4.291 (60), 2.571 (60), 2.050 (50), 2.869 (30)

  • Chemical Composition
    Elements Content 1 Content 2
    H2O 29.90 31.79
    CO2 25.10 25.89
    Y2O3 22.88 33.21
    Na2O 8.64 9.11
    Dy2O3 3.28 -
    Er2O3 2.83 -
    Gd2O3 1.92 -
    Nd2O3 1.41 -
    Yb2O3 1.04 -
    Sm2O3 1.02 -
    Ho2O3 0.90 -
    Tb2O3 0.56 -
    Ce2O3 0.37 -
    Tm2O3 0.27 -
    CaO 0.05 -
    Total 100.17 100.00

  • Optical Properties
    • Transparent to translucent
    • Optical class: Biaxial (+)
    • Pleochroism: In pale colors if cuprian or cobaltian
    • Orientation: Y = b; Z^a = 14°
    • α = 1.480(4); β = 1.498(2); γ = 1.571(4)
    • 2V(meas.) = 53(3)°
    • 2V(calc.) = 55°

  • Estimated Properties
    Electron density Bulk density (electron density) = 2.16 g/cm3
    note: Specific gravity of adamsite-(y) = 2.18 g/cm3
    Photoelectric PEAdamsite-(y) = 87.57 barns/electron
    U = PEAdamsite-(y) x ρelectron density = 189.50 barns/cm3
    Fermion index Fermion index = 0.03
    Boson index = 0.97
    Radioactivity
    Adamsite-(y) is radioactive

How to Identify Adamsite-(y)

Adamsite-(y) can be identified in the field by its color variations, such as white, pale pink, and pale purple. It is sometimes even colorless. It is translucent to transparent, with brittle fracture and spherical, rounded aggregates. It has {001} perfect, {100} good, {010} good cleavage. This mineral has a vitreous, pearly luster, with a white streak.

The hardness of adamsite-(y) is 3 – approximate to calcite.

Global Distribution

Adamsite-(y) is distributed in the following places:

  • Canada - From Mont Saint-Hilaire, Quebec
  • Norway – Nordland, Tysfjord, Hundholmen
  • Russia - Northern region, Kola Peninsula, Lovozero Massif, Alluaiv Mt, Umbozero mine, Shomiokitovoe pegmatite

Occurrence of Adamsite-(y) and Useful Mineral Association

Adamsite-(y) occurs in a rare late-stage, low-temperature hydrothermal mineral in an alkalic pegmatite dike, associated with an intrusive alkalic gabbro-syenite complex.

It is often associated with minerals such as thomasclarkite-(Y), donnayite-(Y), petersenite-(Ce), horvathite-(Y), and rhodochrosite.

References

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