by Tom Herbst
Tearbuncle is a relatively simple and fast teardrop design, BOG optimized
for ISO reflection and tilt.
I designed Tearbuncle to address the general lack of good pear or teardrop
designs that are easy to cut and produce a pleasing reflectance pattern.
The name comes from the shape (obviously), combined with the now obsolete
term "carbuncle," which refers to a red gemstone, usually a
garnet. Sherlock Holmes afficionados may recall the short story "The
Adventure of the Blue Carbuncle," which revolves around an extremely
valuable blue gemstone from China. This stone had "every characteristic
of the carbuncle, save that it is blue in shade." A real blue garnet
would be a valuable find indeed!
Tearbuncle is a straightforward design suitable for all skill levels.
BOG-optimized for ISO (90%) and tilt in Garnet.
At right is a 9x11 mm, 3.3 carat Tearbuncle cut in flawless rhodolite
GemCAD and GemRay output for Tearbuncle appear below. The GemCAD file is available