I wish I had taken a photo of the rough piece of citrine from which this gem was cut. When I purchased the rough, I was looking for material that I could use for concave faceting. It was during of one of my false re-starts for faceting and I don't remember if I thought I would saw the rough into multiple pieces or use it for a single stone. When the time finally came last fall that I took it out of the drawer for faceting, I ended up preforming it to be a single rectangular cushion stone. Other than knowing that I would use the OMF machine to put concave facets on the pavilion, I had no idea how I would cut it. It got dopped along with ten or so other stones. They got cut. This one sat there being big and intimidating. Another ten or so stones were dopped and cut and the big citrine still had not touched the faceting laps. It was now the new year and I decided that I could no longer allow that stone to intimidate me.
The first step was to find the outline and the pavilion keel. I started roughing in the shape with the lap I typically use for such purposes and after a bit realized it needed a coarser lap. Once I got the outline figured out it was time to think about the details with respect to facet placement including the concave ones. The initial pavilion facet pattern was a basic step cut. Typically, that makes for a pretty boring gem. However, concave facets placed in the pavilion usually light up the stone and make it more visually interesting.
I decided on three concaves on each side of the pavilion with a bit of space between them. They were placed such that they centered on the middle step extending towards the keel and the girdle, but not touching either. Often the keel on quartz is easy to chip, so keeping the curves away from that area means that should chips appear in the future as a result of handling, the repair required would be minimal.
Then it was time for the crown. Again, the first step was to level the girdle and rough in the shape. After a good night's sleep, I decided that the crown would consist of flat facets only. Rather than using a routine step crown with a large table, additional rows of facets were used so that they and the table were about the same width. When the stone was removed from the dop, the results were as desired. The long facets on the crown made it seem like there were multiple sets of concave facets on the pavilion.