| Octoburst - designed by Steve Corman networks1@home.com | |
|---|---|
| Angles for R.I. = Angles for R.I. = 1.74 | 65 facets + 8 facets on girdle = 73 |
| 8-fold, mirror-image symmetry | 96 index |
| L/W = 1.000 T/W = 0.507 T/L = 0.507 | P/W = 0.446 C/W = 0.163 |
| H/W = (P+C)/W+0.02 = 0.683 | P/H = 0.701 C/H = 0.269 |
| Vol./W^3 = 0.255 | Brightness at 10 degrees tilt for RI = 1.74
COS = 71.7 ISO = 82.1 |
| Pavilion | |||
|---|---|---|---|
| 90.00 | 96-12-24-36-48-60-72-84 | ||
| 1 | 56.00 | 96-12-24-36-48-60-72-84 | Cut to level girdle |
| 2 | 42.00 | 06-18-30-42-54-66-78-90 | Meet 1-girdle |
| 3 | 40.00 | 04-08-16-20-28-32-40-44-52-56-64-68-76-80-88-92 | Meet 1-2. Cuts very fast! Use slow speed or stationary lap. |
| Crown | |||
| a | 40.00 | 96-12-24-36-48-60-72-84 | Level girdle |
| b | 35.08 | 03-09-15-21-27-33-39-45-51-57-63-69-75-81-87-93 | Meet a-girdle |
| c | 30.21 | 96-12-24-36-48-60-72-84 | No meet. Cut to consistent depth. |
| 00.00 | Table | Meet points of b facets formed by c facets | |
I named this cut Octoburst after the the sunburst pattern in the pavilion. It is very simple, 3 steps each for the crown & pavilion. It has a small number of total facets but the finished stone has a lot of sparkle due to the placement of the small ones. According to Gemframe, it has average ISO brightness of 82.1% over a 10 degree tilt (at RI = 1.74).
Note on crown step c: The depth of this cut is not crucial. The depth shown in the diagram gives a 50% table. A deeper c cut will enlarge the table, but doing this too much shrinks the b facets and decreases the sparkle of the stone.
Editor's note: If you are cutting quartz (RI = 1.54), you should increase the angles for P3 and P2 as the pavilion #3 facets are below the critial angle for quartz.
