Monthly Archives: June 2018

Celestial Celestine

Celestine

  • named from the Latin word caelestis meaning celestial, which in turn is derived from the Latin word caelum meaning sky or heaven because of its often soft blue color
  • pure Celestine is colourless
  • due to lattice defects in Celestine, colour centres are created which give the crystal its characteristic bluish colour
  • these centers are often additionally stabilized by the presence of pottasium ions
  • heating to over 200 °C “cures” these lattice defects and the mineral loses its color
  • radiation with X-rays creates new or more lattice defects and the color returns or can be intensified.
  • Formula: SrSO4
  • Space group: Pnma (No. 62)
  • Crystal system: orthorhombic
  • Crystal class: mmm
  • Lattice parameters:  a = 8.360 Å, b = 5.352 Å, c = 6.858 Å, αβγ = 90°

Picture: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0


Crystal structure (click on the pictures to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • SO4 tetrahedra (yellow)
  • SrO8 polyhedra (green)
  • Oxygen (red)

For a 3D interactive version, see here:

https://skfb.ly/6zG6R

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