Fasscher Design for Tourmaline

A couple months back I found an interesting photo in this thread on the Gemology Online forum. The stone was a colourless YAG garnet in a design that looked very similar to an Asscher cut but with a simple pavilion.
http://gemologyonline.com/Forum/phpBB2/viewtopic.php?f=37&t=14348&p=148768&hilit=#p148768

I was inspired to re-create the design which I’ve dubbed Fasscher for “Fake Asscher”. It is optimized for Tourmaline (RI 1.62) but it should work for RIs higher than Tourmaline also. You can download the PDF or the GemCAD file by clicking on the links:
http://www.omnifaceter.net/designs/Fasscher.gem
http://www.omnifaceter.net/designs/Fasscher.pdf

I cut this in two different Nigerian tourmaline. The nice thing about this design is that it’s rather flat and the crown steps can be varied in height to accommodate thin tablet-shaped rough as pictured below. Note that the colour of the rough lightened considerably once I cleaned off the rind and garbage on the outside of the stones. For the green, the c-axis is the top view (greenish) while the a-b axis is the bright cyan. The pink c-axis is a bit orangy with orange-pink a-b axis. The photos are pretty much unre-touched – I only adjusted the exposure to get the saturation closer to reality.

Nigerian Tourmaline Rough Before Cleaning and Preforming - Side View

Nigerian Tourmaline Rough Before Cleaning and Preforming - Side View

Nigerian Tourmaline Rough Before Cleaning and Preforming - Top View

Nigerian Tourmaline Rough Before Cleaning and Preforming - Top View

 

Nigerian Tourmaline Rough Preformed - Side View

Nigerian Tourmaline Rough Preformed - Side View

Nigerian Tourmaline Rough Preformed - Top View

Nigerian Tourmaline Rough Preformed - Top View

The results? Not exactly the same as an Asscher, but when viewed at a distance it’s a pretty close call. The stones are almost flawless – the pink has a tiny healed fracture near the girdle (please excuse the fingerprints and bits of glue still stuck to the pavilions).

2.05ct Nigerian Mint Tourmaline

2.05ct Nigerian Mint Tourmaline, 7.5 mm square

3.39ct Nigerian Pink Tourmaline, 9.4mm square

3.39ct Nigerian Pink Tourmaline, 9.4mm square

Enjoy!

-Allan

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