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16.39: Hauyne

  • Page ID
    4723
  •  

    Hauyne
    Chemical composition Complex silicate
    Crystal system Cubic
    Habit Dodecahedral
    Cleavage Poor
    Hardness 5.5 - 6
    Optic nature Isotropic
    Refractive index 1.494 - 1.509
    Birefringence None
    Specific gravity 2.44 - 2.50
    Lustre Vitreous to greasy

    File:Hauynecut.JPG

    Figure \(\PageIndex{1}\): Faceted hauyne, 0.26ct

     

    Figure \(\PageIndex{2}\): Small faceted Hauyne
    Eifel District of Germany 
    Photo courtesy of Barbra Voltaire


    Haüyne (pronounced "how-een") is an extremely rare mineral and even rarer gemstone. It was first described, mineralogically in 1807 by René Hauy from who it derived its name. Examples of haüyne are found in association with alkaline volcanic rocks that are primarily located in the vicinity of Laacher See Eifel Mountain district of Germany. The highest prized specimens of Haüyne found in this locality are of an unusual vibrant blue color. Lighter blue to greenish blue colors are found as well. Gem quality material has not been reported from other localities.

    Hauyne's spectrum is diagnostic in the darker blue specimens with a full absorption of the red to green.

    Hauyneqy2.jpg

    Figure \(\PageIndex{3}\)

     

    The lighter specimens fluoresce an intense orangy pink under LWUV.

     

    File:Hauynelw.JPG

    Figure \(\PageIndex{4}\)

    Note the inert stone on the right which is a slightly darker blue hauyne

     

    Geology

    Haüyne, in the Eifel Mountains, formed in a magma chamber, with other minerals which include plagioclase, sanidine, nosean, nepheline, leucite, apatite, olivine and in association other alkaline volcanic rocks, mainly phonolites. It is thought that this eruption occurred 12,900 years ago (geologically a wink of the eye) in three layers. Haüyne occurs in all three layers. The area is commercially mined for pumice and basalt. Hauyne can be collected in these quarries during the weekends.

     

    Figure \(\PageIndex{5}\): Hauyne Crystals

     

    Additional Information

     

    Dr. Edward Gübelin Collection: Hauyne