Forums Beginner Questions Round Brilliant For Sunstone?


  • Round Brilliant For Sunstone?

    Posted by danointhenw on September 3, 2017 at 8:56 pm

    After working on a novice competition stone since what seems like forever, I finished and finally got a chance to put a nice sunstone I had on the dop. A buddy had a diagram for “a round brilliant for sunstone” that has a better angle for sunstone’s RI. After cutting the girdle to width and the P1 cuts, I finally realized that the diagram seems to be laid out for cutting the crown first…oops…
    It then dawned on me that it was probably going to be impossible to cut the crown according to the diagram which shows cutting the table 1st (!??).
    After thinking about it, my question is this, I think I SHOULD be OK if I reverse the crown cuts, I.E., do the C4s first to get my meets at the bottom of where I want the girdle width, and then work my way up to the table.
    Diagram is for a 96 index.
    This stone is either going to be 2cts of awesome sauce or a hot mess and I hope the former.

    danointhenw replied 4 years, 11 months ago 4 Members · 5 Replies
  • 5 Replies
  • tucsonbear

    September 4, 2017 at 1:00 am

    I always cut the table last. Lay in your break facets first and get the girdle thickness you want, then the mains, then the stars. I then polish in the reverse order (stars, mains, breaks). Then the table. My machine won’t go to 0°, so I have to take it out and use a table adapter.

    I have cut a lot of transparent yellowish orthoclase, but I’ve never done any sunstone. Like to see a pic when you’re done.

  • danointhenw

    September 6, 2017 at 7:44 pm

    Thanks TB, I will (if there’s anything left…)

  • gemmakermz

    August 18, 2019 at 8:13 pm

    dano i teach faceting and start with the pavilion/bottom first then top/crown and start from tip to table, working my way up the stone and better control of centering. i have several pounds of Oregon sun stone i got in quartzite Arizona pow wow in 70’s and it all cuts beautiful. if you’d like to try something new and different in a cut i have my own design of my reverse brilliant that really awakes any stone. get in touch with me and i can send you a copy of it with cutting order(bottom first) and a piece of laser yag that will blow peoples minds when cut to it.
    p.s. i polish on tin with 50,000 diamond powder and water, both very slow speed.

  • Lowjiber

    August 20, 2019 at 12:57 pm

    I cut a lot of Sunstone. The important thing to remember is that the Critical Angle is 43.5 degrees. I usually bump my SRB Pavilion angles to 45.5/44 for P1/P2 (vice the SRB 42.5/41.5) to enhance any color in the Pavilion.

    Here’s a tip I learned from John Bailey at The Faceting Academy in Oregon…

    If you have a piece of champagne colored rough that has a small “hint” of color” somewhere inside, place the color as close to the bottom of the pavilion as possible. That really “pops” the color when viewed thru the table.

  • danointhenw

    August 21, 2019 at 5:04 pm

    Thanks Gents! Gemmaker, sent you an email.

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