North by Northwest
by Tom Herbst

North by Northwest is a very simple design. It displays the best properties of both a classic "sparkly" stone and a more geometric reflector. It works well in medium index material such as tourmaline and beryl.

The name comes from the resemblance of the crown and pavilion facets to a compass "rose," the direction indicator on old-styled maps. The pavilion points North, and the crown points Northwest, hence the cinematic name.

North by Northwest is a straightforward design suitable for all skill levels. BOG-optimized for ISO (94%) and tilt in Tourmaline. For beryl, tangent ratio the pavilion from 43.2° to 44.2° and the crown from 32.2° to 40°.

Pictured below is a matched pair (more or less) of 6 mm, 1 carat stones cut in flawless, pale, green-blue tourmaline (left) and synthetic emerald (right).


GemCAD and GemRay output for North by Northwest appear below. The GemCAD file, BOG-optimized for tourmaline, is available here.