You can find cutting instructions for the Gram Prince here.
The Story of the Prince
My customers often ask for rectangular “princess-type” cuts. Surely one or two designs exist somewhere, but I’ve never seen one, let alone one suitable for colored gemstones. It took a while, but I finally developed one worth cutting that matched my Gram Princess design.
Like his sister, the Gram Prince is inspired by the square princess cut so popular in the diamond trade. To be clear, the original princess design concept isn’t mine. Again, I used the name “Gram” to distinguish my redesign from others that may be floating around out there.
The jewelers who’ve seen the Gram Prince have all asked me to cut stones for them in this design. Since it requires a low number of facets and has some flexibility, this design is really a “Money Cut.” It cuts quickly, performs beautifully, and sells well.
This cut is very bright and surprisingly nice despite looking so simple. I like it in almost any medium to light-colored material. It also works well in quartz (70% or so), just add 2° to all of the pavilion tiers, no changes on the crown.
The Gram Prince isn’t hard to cut, but the pavilion tiers and meets cut pretty fast. I find it easier to cut L/W = 1.25 and then cut in P5 and P6. They won’t quite center point (though P7 and P8 will), then cut in the breaks.
You’ll need to change the mast height for C1 at the long and short ends, depending on how you cut.
Notice that this is fairly deep. If your L/W differs slightly, you can tweak the pavilion to make the meets without much trouble. This may come in handy in case you’re trying to fit a piece of rough and don’t want to waste any.
Enjoy cutting your own Gram Prince.
Detailed faceting instructions by Jeff Graham available at The Rock Peddler