by Tom Herbst
I designed Hexpo to get the most out of a beautiful, large, hexagonal
nodule of pink tourmaline. The design worked out amazingly well - this
is perhaps the most visually interesting of the 50 or so stones I have
The name comes from hexagon + expo, since the crown pattern reminds me
of the Expo '67 logo used to celebrate Canada's centenary in 1967 (yes,
I am that old).
Hexpo is a straightforward design, and is appropriate to all skill levels.
BOG-optimized for ISO (84%) and tilt.
At right is a N mm, M ct Hexpo cut in flawless Nigerian tourmaline.
GemCAD and GemRay output for Hexpo appear below. The GemCAD file is available
NEW! Hexpo optimized for USFG
rules (score: 378). GemCAD file here.