|Simple Brilliance (simpbril.gem)|
|Angles worked out on GemCad by Jack Rowland email@example.com|
|Angles for R.I. = 1.54||49 facets + 16 facets on girdle = 65|
|8-fold symmetry||32 index|
|L/W = 1.000 T/W = 0.602 T/L = 0.602||P/W = 0.450 C/W = 0.142|
|H/W = (P+C)/W+0.02 = 0.612||P/H = 0.735 C/H = 0.232|
|Vol./W^3 = 0.214|
|C||42.00||32-02-04-06-08-10-12-14-16-18-20-22-24-26-28-30||Cut to center point|
|G||90.00||32-02-04-06-08-10-12-14-16-18-20-22-24-26-28-30||Level the girdle|
|B||42.00||32-02-04-06-08-10-12-14-16-18-20-22-24-26-28-30||Leave some girdle|
|M||35.00||01-05-09-13-17-21-25-29||Cut to Break-Girdle meet point|
|S||20.00||03-07-11-15-19-23-27-31||Cut to top Main-Break meetpoint|
|T||0.00||Table||Cut to Star-Main meetpoint|
This is just about the ultimate in beginners projects. It is a design I've used for beginners when I teach faceting and it is just about bullet proof. Just about any mistake you can make can be compensated for with some very minor variations. The design can be cut with a 32, 64, or 96 index, but I suggest using the 32 index to start off. The fewer the index settings the less likely you are to have a mishap! I found this design in a native cut garnet. I couldn't believe how nice it looked.
This is a simple round brilliant with the pavilion main facets left off. This means that the pavilion is simply 16 facets that meet at the bottom. I've found that it does not hurt the brilliance or scintillation, and make the stone much easier to cut. The other advantage I'll explain in the "disaster recovery" section.
To start, select a fairly round piece of rough. I recommend sunstone or light colored garnet as a first stone rather than quartz. Both are much easier to polish and polishing is the hardest thing for beginners. You can usually get either one for very little, especially if you recut a poorly cut stone, or one that is damaged. I get fairly large poorly cut garnets in small quantities for about 25 cents a carat. Straw colored sunstone can be had for under $100 a kilo. What you can't cut you can use for gem trees or kid's give-aways.
Grind a flat on the course lap, dop your stone, and cut 2 facets at 42 degrees with index settings of 32 and 16 until a knife edge starts to form in the middle. Once these 2 facets are cut eye-ball that the part of the facet closest to the dop gets at least 1/2 way up the stone. Now cut 2 more facets at index 8 and 24 with the same angle and elevation until a point is formed at the tip of the stone. It is very important that you not apply any pressure as the end of the cut is reached. Even the slightest pressure will cause the stone to overcut.
Now cut the remaining index settings of 2,4,6,10,12,14,18,20,22,26,28,30 to the same 42 degrees and they should all end up at the same meet point at the tip. If they don't you either undercut or overcut some of them. Go all the way around and check again. If some are overcut, drop the elevation down a click or two and try it again.
Once this is done, change your angle to 90 degrees and recut the above index setting to form a level girdle all the way around the stone. Again, use no force, allow the machine to complete the cut. When you have a level girdle all the way around the stone and at least 1/3 of the stone is left for the crown you are ready to go to the fine lap. If you don't have a level girdle because of flaws, cracks, etc. at this point you either need to cut more at 90 degrees, or go back and recut at 42 degrees.
Now shift to the fine lap, recut the GIRDLE facets at 90 degrees, then recut the pavilion facets at 42 degrees. You don't need to remove a lot of material at this step. Just cut away the big scratches left by the course lap. I use an indelible marker and paint the facets black. When the ink is cut away, so are the scratches! Cut very carefully and evenly and make sure you end up with all facets meeting at the tip, and a nice, level girdle line. If you can't do this it is because you are either overcutting by using pressure, or not allowing the cut to finish (undercutting).
Without adjusting the height, clean the lap and the stone. Put the UltraLap on your fine lap (flooded with water) and polish the 16 pavilion facets using moderate pressure. Do not polish the girdle. Polish with the lap almost, but not quite dry.
Transfer the stone and cut the 16 BREAK facets. These are cut to the same index settings as the pavilion facets. If you have a lot of material to remove use the course lap, if you don't have much use the fine lap. Leave enough girdle if you are using the course lap to allow a little more to come off with the fine lap. Once all 16 facets have been cut with the fine lap you should have a nice level girdle. If you don't you either did not get the stone properly aligned after transfer, or again you are undercutting or over cutting.
Now cut the 8 MAIN facets to just shy of the GIRDLE/BREAK meets. These should look like they touch with the naked eye, but should not quite touch when using a 10 power loop. They should all be cut to exactly the same depth by allowing the machine to finish cutting WITH NO PRESSURE APPLIED. If I'm sounding like a broken record, forgive me, but until you can apply consistent pressure, don't use any! Most of the mistakes I see with cutting are wrong index setting, wrong angle, wrong height, and TOO MUCH PRESSURE. If you undercut, you can go back and finish it up. If you overcut, you need to recut all the facets you've cut before it.
Cut the 8 STAR facets to just shy of the MAIN/BREAK upper meet point. Again, they should appear to meet with the naked eye, but not quite with the 10 power loop. Now polish the STARS, MAINS, and BREAKS.
Transfer the dop to the 45 degree dop, and cut the table with the fine lap. Set the angle to 45 degrees. Cut carefully until you almost reach the first STAR/MAIN meetpoint. Look to see if all or just some of the meets are going to hit at the same time. You may need to adjust the angle up or down or cheat the index a little left or right to get the most meets to hit at the same time. You may only get 3 meet points to come in on your first stone. Don't worry, just don't overcut them to make the others come in. Again, use the trick with the indelible marker to make fine adjustments. This allows you to see what has been cut and what hasn't. Once you get it as close as you can, clean the stone, and polish and you are done! Just clean the wax off the stone with alcohol and enjoy!
Disaster Recovery: If you cut away the girdle on the crown, or overcut the MAIN or STAR facets, just recut the girdle and start over. You can do this until you start to cut away the dop stick. There are no meet points to mess up on the girdle by recutting, so this works well. You just get a smaller stone. If you end up cutting the dop stick it is time to cut another stone. Practice makes perfect! If you blow the STAR facets, drop all the angles down 5 degrees and recut the crown.
If the stone ends up very small, leave out the STAR facets. Below about 6mm you can't see them with the naked eye. Cut the table until it is about 50% the width of the stone and you have it. This is called a "PETAL CUT".
If you mis-index the mains and cut 16 mains instead of 8, leave out the STAR facets and finish the same as the "PETAL CUT".
Index of Gem Designs
Perfect Transfer Index
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© Bob's Rock Shop Bob Keller