Primarily, the choice between the two is influenced by such factors as the carat weight of the rough diamond, and the inclusions present in it. Most diamonds are octahedral in shape, making them perfect for brilliant cuts. This is one of the reasons, why this cut is highly preferred.
Additionally, this option does not waste too much carat weight and maximizes the triple qualities of fire, scintillation, and brilliance. By the time polishing and cutting is done, the stone ends up looking truly marvelous and fit for the finger of your beloved.
Non-octahedral rough diamonds are usually cut into fancy shapes, which means it is not a brilliant cut. That includes step cuts that, unlike the round cut, has facets placed parallelly, and produces a minimal look. A step cut mainly features a diamond shape that is rectangular or square, with the facets arranged in parallel rows. The name of the cut draws from the arrangement of the facets, which look larger than in a brilliant cut and resemble steps on a stair.