I have a diamond ring where the diamond is triangular. While most diamond crystals are octohedral, some crystals are cube-shaped, so I was wondering if they start preparing a finished triangular diamond by cutting the corner off a cube. It seems to me that with any octohedral crystal, you would waste too much of the diamond trying to fashion a triangular finished stone.
If not, how do they cut a rough diamond into a triangle?
When they cut any shape of diamond, they waste a lot of it. My understanding, based mostly on a visit to a diamond factor in Amsterdam a few years ago, is that they take a rough diamond, cleave it along flaws, and take what’s left and round it. Then they carve facets out of what’s left, which wastes like half of what they started with. I would imagine that they pick the cut based on the diamond’s natural shape and characteristics so that the finished stone looks as good as possible.
Of course, I am not a diamond cutter and I’m sure somebody who is will come along any moment to tell me all how wrong I am. 