The step cut is also known as the trap cut. The name step cut is derived from the step-like shape of the diamond that results from this cut. The resultant shape can be square, rectangular or trapezoid, depending on the desired effect.

The table and girdle in step cuts are each long planes, either square or rectangular, with long parallel facets with four sides. The number of facets varies from diamond to diamond, depending on the particular shape and size of the diamond. The culet in the step cut type of diamond is referred to as its keel. Step cut diamonds with color are cut in order to place the color as deep into the pavilion as possible, to have the color appear to flood the entire diamond when looked at through the table.

The squared shape of this diamond type can put diamonds with this shape at risk for chipping, and so the corners are often cut away, making the cut-cornered look of the Emerald and Asscher cuts. Step cut diamonds do not have the brilliance or fire of the brilliant cut shapes, due to their shallow crown and pavilion. However, they are able to preserve much more of the original rough carat weight than the brilliant shapes. Shapes with the step cut include: Emerald, Asscher and Baguette, as well as other fancy shape side stones.