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.
By Jeff R. Graham 1 minute read

Simple Portuguese gem design by Jeff Graham © 2001.

You can find cutting instructions for the Simple Portuguese here.

Cutting Remarks

Simple Portuguese-cut rubellite - Nigeria

A Simple Portuguese, 10.3 cts and 14 mm x 9.2 mm deep, cut from a top Nigerian rubellite tourmaline by Jeff Graham. You can follow the step-by-step faceting process for this gem 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.

Simple Portuguese - array

Random – Cosine – ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler