by Tom Herbst
I designed KeyStar to isolate the clean part of some beautifully coloured
but significantly included Rubellite tourmaline. The design is new, although
I have taken some inspiration from the excellent "Pat's Points"
design by James Graham.
KeyStar is a straightforward design, and is appropriate to all skill
levels. Note that P11 to P15 can be eliminated for small stones, or for
a somewhat different look.
At right is a 0.9 carat, 5x6 mm Keystar cut in flawless Nigerian Rubellite.
GemCAD and GemRay output for KeyStar appear below. The GemCAD file is available
here. Note that the dark areas in the GemRay
trace are trapped rays, and the corresponding region of the stone above returns