Simple Portuguese: Online Faceting Designs & Diagrams
The Portuguese cut works wonderfully for very deep gemstones with high refractive indices. Jeff Graham’s Simple Portuguese, a modification of this classic, is designed for large gems with lower refractive indices.
You can find cutting instructions for the Simple Portuguese here.
My redesigned Portuguese cut has one less tier on the pavilion than the original. That's why I call it "simple." Although it still has a lot of facets, my redesign is really quite easy to cut. It will also show more interesting reflections through the table. In both the photo and the ray trace, you can see the starburst on the culet through the table. I think the old style lacked this.
For this design, I suggest a light colored material and, obviously, a large stone. (My rubellite had more of a medium than light saturation). Cut this in refractive indices 1.62 to 2.14 (90.4%) with no changes. The ray trace is only in the high 70s, but note there's no light lost through the pavilion (except near the girdle). This design brings out the dispersion in finished gems.
Enjoy cutting your own Simple Portuguese.
Detailed faceting instructions by Jeff Graham available at The Rock Peddler
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