by Tom Herbst

I designed Topo to teach myself how to do checkers. The combination of a classic brilliant-type pavilion with a checkered crown produces a truly spectacular stone.

Topo is a simple and fast design, BOG optimized for ISO (94.5%) and tilt in topaz. The table can be omitted for smaller stones.

The name is yet another literary tour de force. The original GemCAD file was called TopO for "Topaz: Oval". Ahh, how deep run the wellsprings of creativity...

At right is a 9x13 mm, 6.5 carat Topo cut in flawless topaz.

GemCAD and GemRay output for Topo appear below. The GemCAD file is available here.