Zircon

Assalamualaikum.. well, this is my birthstone.. hihi..

Chemistry: ZrSiO4, Zirconium Silicate
Class: Silicates
Subclass: Nesosilicates
Uses: Gemstone and mineral specimens

As a mineral specimen, zircon is uncommon in most rock shops because attractive specimens are rare. However, fine specimens of well shaped zircons are available and are in demand. The typical simple crystal of zircon is a tetragonal prism terminated with four sided pyramids at each end. The prism may be lacking and the crystal can look octahedral. More complex crystals have faces of a less steeply inclined prism that taper the terminations. Also a secondary prism may truncate the primary prism by cutting off its edges and producing an octagonal cross-section through the crystal. There is even an eight sided pyramid (actually a ditetragonal dipyramid) that may modify the four sided pyramids. As you can see, zircon crystals can go from a very simple crystal to a rather complexly faceted form.

PHYSICAL PROPERTIES

  • Color is brown, red, yellow, green, blue, black, and colorless.
  • Luster is adamantine.
  • Transparency crystals are transparent to translucent.
  • Crystal System tetragonal; 4/m 2/m 2/m
  • Crystal Habits: dipyramidal and prismatic as discussed above.
  • Cleavage indistinct in two directions, prismatic.
  • Fracture is uneven
  • Hardness is 7.5
  • Specific Gravity is 4.6-4.7
  • Streak white
  • Associated Minerals albite, biotite, garnets, xenotime and monazite.
  • Other Characteristics: is sometimes fluorescent and darker crystals may be radioactive due to impurities of rare earth elements. Also index of refraction is 1.92 – 2.01
  • Notable Occurances Seiland, Norway; Pakistan; Russia; Bancroft and Sudbury, Ontario, Canada and New Jersey and Colorado, USA.
  • Best Field Indicators are crystal habit, hardness, luster and density.
Published in: on August 30, 2008 at 10:44 am  Leave a Comment  

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