I've cabbed a few but only one decent-sized one. A jeweller I know was out the other day checking out my new faceting machine and he spied the star (it's about 15 carats finished) and wanted to buy it to make a ring for himself. I was pretty happy, I must have done an ok job if a jeweller wants to buy something I have done. Most likely we'll just do a trade, the star for a nice piece of bling for wife.
The star does have to be oriented Varts. It shows
across the crystal, imagine a six-sided quartz crystal sliced across so you're looking at a hexagon. It's on the face of the hexagon that the star will show, not down the length of the crystal. If you cab it the wrong way I'm told you end up with as little tiny star squashed down in a corner of the stone or none at all. Where the gold/bronze sheen shows the strongest is where the star will lie, a bit of honey on the rough stone helps it show. Put that sheen smack in the middle of the cab.
Shape the cab as normal. When you start smoothing it, don't use any fixed grits like a cabbing wheel over about #600. I had hell trouble polishing the thing, the surface just kept peeling. Probably because it contains so much rutile that the softer rutile crystals chew away faster than the much harder corundum and it sort of undercuts and little bits flake off. Everything over #600 must be
loose diamond grits in the bit of experience I've had with them.
A flat surface ground on the back of the one above.
