Australian Facetors' Guild Limited

Pushing the boundaries in competitions.

  • 26 Jan 2020 10:18 PM
    Message # 8685880

    I am cutting some zircon and ended up with micro chips on the crown facet/girdle facet boundaries.  My solution is to cut some micro facets using 100k grit on a ceramic lap.

    I end up with continuous facet boundaries which I measured at between 0.05 and 0.025mm using the corresponding lines on my graticule.  These facets would, if they were girdle facets, be too small to judge, they are not visible to the naked eye.

    This stone is not a competition stone, but one for my wife.  But it got me thinking about whether doing the same on a competition stone would disqualify it for adding extra facets.

    Any thoughts?

  • 27 Jan 2020 1:00 PM
    Reply # 8691223 on 8685880
    Anonymous member (Administrator)

    Yep! as you've changed the design from what the competition schedule says. They would be detected with a 10x by the Judge even at those small measurements. You will be surprised how minute some facet edges are, light will reflect of that flat faced edge. It's judged under "Facet Edges Sharp" see the photo attached, that edge actually varies in width.

    Quite all right for non comp stones.


    1 file
  • 27 Jan 2020 4:09 PM
    Reply # 8692136 on 8685880

    I noticed I was getting tiny chips on the facets next to the girdle on this years Zircon comp stone. First time I’ve cut Zircon in over 20 years, so didn’t remember it was a problem.

    Just had to spend longer on the 3k BATT pre polish to cut them out.

  • 27 Jan 2020 7:31 PM
    Reply # 8693317 on 8685880
    Anonymous member (Administrator)

    Probably caused by fractures from too coarse a cutting lap? i cut a bit of red zircon from Oberon area and find using a well worn 600 works better even a 1200 then prepolish on 3000 then polish 14k on CAT. They are small stones final size about 5, 6, 7 mm

  • 28 Jan 2020 1:54 PM
    Reply # 8696755 on 8685880

    Hi Paul,

    I've noticed at certain angles, even sharp facet boundaries will throw a reflected line.



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