CANADIAN MINING NEWS

 

Moissanite Could Add Sparkle to Cabo's Diamond Discovery                            by R.A.Gilson- January 30, 2003

  • In a January 27th, 2003 news release, Cabo Mining Corp. announced that " A channel sample collected in July, 2002 from lamprophhyric breccia overlying Hole CC-14 located 2 additonal diamonds as well as 14 blue-green mineral grains, initially identified as 'coesite', a high temperature quartz. These grains are now believed to be 'moissanite', a silicon carbon mineral known to be associated with ultramafic rocks and indicitive of  conditions suitable for diamond preservation. Several grains are being returned to Saskatchewan Research Council for positive identification using a quantitive microprobe analysis.
  • Moissanite is a mineral that was first discovered in fragments of the meteorite at Diablo Canyon or Meteor Crater in Arizona. It was named in honor of its discoverer Nobel Prize winner, Dr. Ferdinand Henri Moissan.

    Natural moissanite is very rare and gem quality stones would likely demand a high price since laboratory grown sample are only slightly less expensive than diamonds due to the difficulty in growing the crystals.

    Moissanite grown in laboratories is now being cut as gemstones and they are used as diamond simulants. Moissanite brings to the jeweler's table a similar index of refraction and better than twice the fire of diamond, but is only slightly less expensive due to the difficulty in growing the crystals. Moissanite is causing quite a stir in the jewelry markets.

    As a diamond simulant, artificial moissanite is very hard to differentiate from diamond and can fool many gemologists. It does have many similarities. It is very hard at 9.25 (diamond is 10) and it is highly refractive with an index of refraction of 2.6 - 2.7 (diamond's IR is slightly lower at 2.42). Most important, moissanite and diamond are thermally conductive unlike other diamond simulants and unfortunately it is this property that is used as the test for the authenticity of real diamonds. Differences however are clear and other tests can be used to differentiate the two. First of all, moissanite is hexagonal, not isometric and therefore it is doubly refractive unlike diamond. A close look at moissanite gemstones should show double facet edges whereas diamond's cut edges are singular in appearance. Moissanite is also slightly less dense than diamond and is rarely perfectly clear of color, having pale shades of green. Also natural flaws are absent in moissanite replaced instead by tiny, unnatural, white, ribbon-like structures that are a result of the growing process. The synthetic SiC known as carborundum has seen many uses in hightech ceramics, electrical components, abrasives, ball bearings, semi-conductors, extremely hard saws and armor.

    Natural moissanite is very rare and is limited to iron-nickel meteorites and a few other rare ultra-mafic igneous occurences. Initially there were skeptics to the original meteorite findings and were attributed to the silicon carbide blades that may have been used to saw the type specimens. But this has been disputed because Dr Henri Moissan did not use silicon carbide blades to prepare the samples.

    There are several phases of SiC. The original mineral discovered is officially known as moissanite-6H. The (6H) refers to the hexagonal symmetry of this phase of moissanite. There are two other phases recognized as minerals: moissanite-5H and the isometric phase beta-moissanite.

    Moissanite is classified as an element despite the fact, that in chemical reality, it is a compound! The reason for this is that the elemental bonds that exist between carbon and silicon are very similar to the carbon-carbon bonds of other elemental minerals such as diamond. There also is just no other mineral class that moissanite could fit in better than the Native Elements Class! Moissanite in fact is sometimes placed into the Carbon Group which includes diamond and graphite. Additional justification lies in the structure of moissanite which is similar to the structure of diamond. Other chemically unusual Elements Class minerals that are found in meteorites include osbornite {TiN}, cohenite {Fe3C} and schreibersite {(Fe, Ni)3P}.

    Since the diamond bearing lamprophyre rocks on the Cobalt property are petrologically similar to the Wawa intrusions, perhaps Moissanite also exists in that region of Ontario and has simply gone unnoticed. A reminder to all exploration Companies to keep an open mind of the potential of discovering new potential, aside from the product they are seeking.

    Moissanite could add sparkle to Cabo's diamond discovery in the Cobalt Camp as well as the Wawa area, both in Ontario, Canada. Time will tell!

    For more information on Moissanite: http://mineral.galleries.com/minerals/elements/moissani/moissani.htm

     

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