Forums General Discussion 2020 International Faceting Challenge

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  • 2020 International Faceting Challenge

    Posted by JTheesfeld on February 26, 2019 at 4:53 pm

    The very beginning of the USFG was based on a USA Team of Faceters, getting together to share information about the Australian, International Faceting Challenge (IFC). That tradition continues on today, as an individual, as well as a Cup Team challenge.

    As the USFG Historian, I would very much like to keep that tradition alive, and help organize the next generation USA Team of faceters, for the IFC Cup. The AFG has asked me to be the USA Co-Coordinator for the 2020 IFC, and I have accepted.

    The USFG is represented in 1 of the 5 competition designs, “The Queen’s Fancy”, by USFG’s very own Ernie Hawes. There have been many changes to the IFC which should be attractive to this “Next Generation” competitor. The faceter may choose any 3 of 5 designs, one of which is a concave cut design. There is also the Section C, “Open design” where the faceter must generate their own cut pattern, as part of the scoring for that gem. Also, participation is FREE!!!…see IFC details below.

    The latest IFC announcement, designs and rules can be found at:

    Please contact me with any questions about this competition. I encourage/challenge everyone, around the world, all USFG international members, old and new, to participate in this historical 2020 competition. Best of luck!!!

    Jeff Theesfeld
    USFG Historian

    History of the International Challenge Cup Competition

    JTheesfeld replied 5 years ago 5 Members · 7 Replies
  • 7 Replies
  • keithwyman

    May 25, 2019 at 10:59 pm

    Greetings, Jeff —

    I haven’t seen much about the IFC and am wondering how it is coming along. Look like they fixed a few things that were glaringly wrong — mostly to do with the dimensions give to the nearest 0.01mm. Most faceters don’t have calipers and mics that are capable of measuring to that level with any kind of accuracy and I know I wouldn’t risk the anvils on my B&S mic on a stone (or risk chipping the stone with the mic). I’m still a bit confused when the size is listed (see sections B, C, and D)as minimum 10mm +/- 0.1mm. What’s with the +/- 0.1mm? Or are they specifying the size to be 10mm, +/- 0.1 mm?

    How many cutters are you working with so far? I’ve gone back through Charlie Moon’s old correspondence from when he was the US coordinator and am amazed at how much effort he (and a number of the cutters) put into the competition. Since you are also the historian in addition to being the coordinator, you might be interested — let me know.

    All the best,
    Keith Wyman

  • gordonperkins

    June 1, 2019 at 9:57 am

    Hi Keith,
    Don’t read too much into the minimum size +/- 0.1mm. I’m on the committee for the AFG’s 2020 Annual Comp and raised it with the official concerned. His view was that if we change the +/- 0.1mm people would be confused because they are so used to seeing the tolerance it expressed that way.

    Minimum size means the minimum size stated with a tolerance of 0.1mm (e.g. size – 0.1mm is accepted).

    The Australian Facetors Guild has a forum on its website where we raised some of the mistakes you saw corrected. Like the USFG, you’ll need to create a login before you can contribute to the forum, but feel free to do so. I’ve always proceeded on the basis that if you don’t know maybe someone else doesn’t know either and asking the question helps build everyone’s understanding.

    The address of the forum is

    When measuring minimum size, be careful to read the competition schedule and measure the stone as the schedule says. This year one of the entrants in the AFG 2019 annual comp measured the minimum size using the direction of W on the gemcad diagram only to find the correct measurement was under the local rules the shortest distance across the outline (flat to flat and not point to point). The IFC committee made a set of rules in the competition schedule and they are not necessarily the same as the Australian local rules in all respects.

    One example is that the minimum size on the Zircon is measured across the longest axis of plan view , instead of the shortest distance on the outline traditionally used in Australia.

    May the best team win.

    Gordon Perkins

  • keithwyman

    June 11, 2019 at 7:00 pm

    Thank you for your response, Gordon. Not to belabor the point, but the minimum size would really be 9.90mm with a +/- 0.1mm tolerance for a 10mm size. Not really a big issue, but at the level of an international competition, all issues are important to be clarified.

    I also appreciate the link to your forum — some very interesting reading there.

    All the best,
    Keith Wyman

  • gordonperkins

    June 12, 2019 at 4:09 am

    Hi Keith,

    Not really, the 0.1mm tolerance is to allow for variations in the calibration of the calipers used to measure the diameter of the stone. It really means that the minimum size is 10.0mm but if the Judge measures the stone at 9.9mm then the stone won’t be disqualified. If you adopt the philosophy that the minimum size is really 9.9mm then you run the risk that the judge will measure the stone at less than 9.9mm and disqualify it.

    Regards Gordon

  • Alan Balmer

    June 12, 2019 at 1:08 pm

    Keith is right – the specification is poorly written, even allowing for language differences. It sounds like any size over 9.9mm is OK. There’s no ambiguity in the SSC’s straightforward “Width: 10mm +/- 0.1mm”.

  • Frankwood

    June 12, 2019 at 11:44 pm

    I recently brought this minimum size tolerance subject up on the Australian forum.
    Stating a required stone size of 10mm +/-0.1mm is easy to understand. The stone has to be between 9.9mm and 10.1mm or it will be disqualified.
    Stating a minimum stone size of 10mm +/-0.1mm to me doesn’t make sense. You can cut the stone any size you like as long as it’s not smaller than 9.9mm.
    To me it would be much simpler to understand if there was no tolerance stated and the minimum size is 10.0mm. It’s down to the cutter to know how accurate his measuring equipment is, which he needs to know anyway when cutting a stipulated size stone to within 0.1mm.
    The judges can apply a 0.1mm tolerance when measuring the minimum size just the same as when measuring a stipulated size.

    Frank Woodward.

  • JTheesfeld

    July 7, 2019 at 3:23 pm

    Thank you all for your input. Sorry I have been absent from this discussion, as I have had much difficulty signing in to the USFG site.

    I am concerned that anything I add to this discussion will make an already confusing minimum size rule more confusing. My understanding is that there is no actual maximum gem size specified. So the way to stay well away from this issue is to keep your final gem size well above 10 mm. Anything over a final 9.9 mm is acceptable, as explained by Gordon above.

    I wish you much success!

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