Designs cuts
Below you will find an example of a design from a friend of mine, which is done on a computer that can do light ray tests, light return, biofringences, light skillanation, color return, and brilliance. For this reason, I use this author's designs over those of others .
Simple Portuguese - Cutting Remarks
Shown at left is a 14mm x 9.2mm deep ~ 10.30 carat "Simple Portuguese " cut from Top Nigerian Rubellite Tourmaline by Jeff Graham.
Simple Portuguese by Jeff R. Graham 
| Simple Portuguese - designed by Jeff R. Graham ©2001 |
|---|
| Angles for R.I. = 1.62 | 129 facets + 16 facets on girdle = 145 |
| 16-fold, mirror-image symmetry | 96 index |
| L/W = 1.000 T/W = 0.461 T/L = 0.461 P/W = 0.447 C/W = 0.207 | H/W = (P+C)/W+0.02 = 0.674 P/H = 0.663 C/H = 0.307 |
| Vol./W^3 = 0.237 | Brightness at 0 degrees tilt for R.I. = 1.62
77.4% Light Return |
| Pavilion |
|---|
| P1 | 48.00 | 96-06-12-18-24-30-36-42
48-54-60-66-72-78-84-90 | Cut to center point. |
| P2(G) | 90.00 | 96-06-12-18-24-30-36-42
48-54-60-66-72-78-84-90 | Cut a level girdle, meet P1. |
| P3 | 43.00 | 03-09-15-21-27-33-39-45
51-57-63-69-75-81-87-93 | Cut to meet girdle. |
| P4 | 41.00 | 96-06-12-18-24-30-36-42
48-54-60-66-72-78-84-90 | Cut to meet P1. |
| P5 | 39.00 | 03-09-15-21-27-33-39-45
51-57-63-69-75-81-87-93 | Cut to meet P3. |
| Crown |
|---|
| C1 | 42.00 | 96-06-12-18-24-30-36-42
48-54-60-66-72-78-84-90 | Cut to meet girdle. |
| C2 | 38.00 | 03-09-15-21-27-33-39-45
51-57-63-69-75-81-87-93 | Cut to meet girdle. |
| C3 | 34.00 | 96-06-12-18-24-30-36-42
48-54-60-66-72-78-84-90 | Cut to meet C1. |
| C4 | 30.00 | 03-09-15-21-27-33-39-45
51-57-63-69-75-81-87-93 | Cut to meet C2 |
| T | 0.00 | Table | Cut to meet C3, C4. |
From an article by Jeff Graham
This is a redesign of the old style "Portuguese" cut. I have modified it to be cut in lower refractive indexes. This design has one less tier on the pavilion than the original. Which is why I call it "simple", this is really quite easy to cut although there are a lot of facets. I designed "Simple Portuguese" to have more interesting reflections through the table (notice that you can see the star burst on the culet through the table in both the ray trace and the finished Rubellite) table, which I think the old style one lacked.
I suggest a light colored material and obviously a larger stone for this design. Cut this in refractive indexes 1.62 to 2.14 (90.4%) with no changes. The ray trace is only in the high 70's, but notice that there is no light lost through the pavilion (except for near the girdle). There is a bunch of dispersion in this design when it is cut and like I said, I suggest light to pale material. Although my Rubellite Tourmaline is more of a medium saturation...
Note to fellow gem cutters: enjoy cutting your "Simple Portuguese"... Drop me an email to let me know your results and what you've cut, or feel free to inquire if you have any questions or need some help regarding this design.
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