Faceting Pendulums to Feature Inclusions

By Mark Oros

I have always found inclusions in minerals fascinating. The other day, I was going through 150 pounds of old stock rutilated quartz that I had received as part of my purchase of the Creative Gems natural facet grade rough business. Being an admirer of inclusions and thought I would facet and cab several select pieces of the rutilated quartz.  After I was finished, I was satisfied with the resulting gemstones, but I was not excited about the the presentation of the rutile in the quartz. It then occurred to me that these minerals could be better appreciated and displayed if I could cut a gemstone that could be viewed at 360 degrees. This thought, along with the long nature of the rutile needles in the quartz, suggested using an elongated design. Stretching out the design and allowing for a 360 degree viewing led to using the form of a pendulum.  

In my first sketches, the pendulum form initially looked smooth and cabochon like.  Although I was getting the full view of the rutile and other inclusions, the design was somewhat less than flashy.  This is when I decide to facet the pendulum. Faceting an elongated design of 1 to 3 inches created some design and faceting challenges for me with my current set of tools.  This is where the fun began.

Once I had the design and process for cutting a faceted rutilated quartz pendulum, I then needed to solve the design challenge of presenting the gemstone as an attractive piece of jewelry.  Here again, my goal was to display the finished gemstone in such a fashion that the beholder could enjoy the finished piece from all angles. I quickly decided to carve a concave girdle into the pendent. This would allow me to grasp the faceted pendulum without having to cover the gemstone with a bulky metal structure. The concave girdle worked out better than expected and my talented local fine goldsmith was able to come up with a simple but sophisticated technique for using the concave girdle to suspend the faceted rutilated quartz pendulum from a chain.  Here is the tutorial on how I designed, faceted, and put in a concave girdle for my rutilated quartz pendulums.

Designing the Pendulum
After sketching it with pencil and paper, the GemCad application was my primary tool for designing the faceted gemstones. This is where I ran into my first challenge. The GemCad application is programmed to design traditional gemstone proportions. In order to get the full design in GemCad, I had to create three separate drawings. The first drawing was the crown and girdle of the pendulum. The second drawing was the girdle and top half of the pavilion.  The third drawing was the bottom half of the pavilion and culet. By combing these three GemCad designs, I was able to piece together the whole pendulum.

Three designs from GemCad for full pendulum

Tips for Faceting the Pendulum
I start with faceting the pendulum on the crown.  The crown is a better finished shape to provide a snug fit in the dop when transferring the gemstone.

Pendulum preform ready to cut the crown first

I carve off half of the preform (dop end) at a slight angle so I do not spend more time than necessary cutting an elongated 90 degree facet (see picture).  I did this with my Diamond Pacific Genie.

Preform tapered on the dop (pavilion) side to save faceting time

I do not polish the girdle given that it can be significantly long and I will recut the girdle when I facet the pavilion.

Given the length of the pendulum, I needed a transfer jig that was longer than the traditional ones.

This is an older and longer transfer jig than I normally use to enable the transfer of long stones

When faceting the pavilion of the pendulum, I was sure to hold the stone and not the mast handle.  Given the length of the stone, I did not want to put stress on the stone/dop attachment.

Holding the stone for less stress on the glued dop attachment area

Given the length of the stone, I might need to use a mast riser for the lower pavilion facets and culet.

Using a 2” mast riser to put in the culet on an ULTRA TEC V5 faceting machine

I took my time when cutting the pavilion.  This could be a very large surface area to facet.  This was made easier by pre-polishing the facets with the Hyper-Edge 8,00 grit diamond lap. www.hyper-edge.com

Faceting large surface areas

I usually add a culet to the pendulum so the it does not stab the person wearing the jewelry.


Fantasy Carving a Concave Girdle
I use a diamond coated V Wheel on the ULTRA TEC Fantasy Machine to carve the concave girdle.

I did a test cut to with the index in a fixed position to make sure I had the right alignment and depth.

Without adjusting the height of the mast, I lock out the segment so that the index gear can free rotate and carve the concave girdle around the complete stone.

I lower the stone if I need a deeper concave.

I use a phenolic V Wheel with diamond to bring the concave girdle to the desired polish.

Polishing the concave girdle on the ULTRA TEC Fantasy Machine

Gemstone Setting
The gemstone is set by creating a large jump ring and twisting the two opposite sides until the ring fits snugly in the concave girdle.  Then, attach another ring over the top of the stone and fasten it into the first ring eyelets and add a bail to the second ring.

Simple gemstone setting

Taking it Two Steps Further
After I did eight rutilated quartz pendulums, I started experimenting with other gemstones, moldavite, sugilite, and opal. The opal was from the Welo District of Ethiopia and is one of my favorite gemstones to facet, although one has to be very careful of the opal’s soft nature. This faceted opal pendulum came out looking somewhat futuristic, so I sent it to my progressive jewelry design friends at Buffalo Craft Company for setting. They designed a fascinating piece made out of white gold and diamonds to cradle the opal.  In order to attach the setting to the concave girdle of the pendulum without stressing the opal, the innovative goldsmith at Buffalo Craft Company fabricated a multi-component setting that interlocked and screwed together, safely nestling the opal in a stunning piece of modern jewelry.

Additional pendulums can be seen at gemstone broker, Adam Pollack’s website:  www.apcoloredstones.com