THE SOUTHERN CROSS - A CROSS CUT OF CONTRASTS
By Liz (Burnett)Kuhns

Who would have thought an innocent walk on the beach would be the first steps in creating a wonderful new gemstone cut, a cut perfectly suited to transparent gems with a high refractive index, especially diamond.

As with all successful gem cut designs, absolute mathematical precision is on top of the list of requirements and such precision and order is clearly visible in the new square brilliant cut called The Southern Cross, the latest gem creation by Dr Duncan Miller. The angle of this cut is based on the refractive index of a stone and the higher the refractive index, the more beautiful the cut. This cut creates an excellent prismatic effect which displays a gem's dispersion to a much higher degree and enhances the brilliance of such stones. Though not quite on a par with the Princess Cut or the Barion Cut, the Southern Cross Cut can be regarded as the ideal square cut design as it only requires 28 facets as opposed to the 62 of the Barion Cut for instance. This makes it an easier and quicker cut, saving both time and money.

So what exactly is The Southern Cross Cut and how can a brilliant cut also be a square cut?

Firstly, the definition of a brilliant cut is a design consisting of triangular facets arranged to radiate from the centre of the stone towards the edge. Due to the nature of this cut, it lends itself perfectly to circular shaped designs, as seen in the ever popular round brilliant cut. Cutting a square shaped design with triangular facets therefore creates the square brilliant cut, as seen in the Princess Cut, Barion Cut and now The Southern Cross Cut.

You may wonder what is so extraordinary about such a design. Well, this is not just an excellent example of contrasts, but also one of carefully calculated precision and perfection.

"The facet angles, measured from the horizontal and required for each set of facets, vary with their number and placement and the refractive index of the gem material used," Miller explained.

The Southern Cross Cut is characterised by triangular facets arranged in pairs of fans, with their focal points offset by ninety degrees on the crown and the base of a square stone, each side at a different set of angles to give rise to a myriad of internal reflections, thus creating the brilliance and scintillation.

The art of cutting a truly spectacular gem that is filled with fire and life, requires that the shallowest base angle of your design should not be the same or less than the optical critical angle of the gem material being cut. As simple as that. Reason enough why the thorough understanding of crystallography is so important.

Gem cutting can be a mixed experience of elation, frustration and satisfaction. Most cutting specialists can relate to this. The disappointment when a beautiful stone undergoing your best ever cutting, suddenly, after many long hours of pure dedication, fracturing and breaking, or an internal flaw mysteriously revealing itself where you could swear there was none, can leave one totally despondent. However, the rewards of gem cutting can be just as intense. It can range anywhere from sheer jubilation to overwhelming awe when the exquisite beauty is subtly teased out of a very ordinary looking rough stone. This takes artistic talent and such an artist is Miller, a perfectionist when it comes to gem cutting. Talking to him in his studio in Cape Town, he explains further:

"... for every disappointment there are numerous rewards - a new cut that exceeds expectations when you get the angles just right, the pleasure of cleaning the wax off a finished piece and suddenly a lump of stone has become a gem."

It takes a strong affinity with nature to create such beauty and not many people can boast to have a better understanding and appreciation of the earth and the beautiful gifts she offers us than Dr Duncan Miller. A self taught gem cutter, he started with gem faceting when still a high school student with the help of the tried and tested training guide "Faceting for Amateurs" by Glen and Martha Vargas. He soon mastered the techniques, as well as his new Ultratec cutting machine. The inspiration gleaned from those early days of mineral collecting and looking for stones to cut led to his first qualification in gemmology when he passed his FGA exams, the top British qualification in gemmology. But that was not enough. His quest for knowledge about the earth led him to a degree in Geology, followed by a doctorate in Materials Engineering and another doctorate in Archaeology. All of which today stand him in good stead when it comes to gem faceting.

Why is there such a desire to facet gems and bring out their inner beauty? For each gem cutter this answer is different and based on a personal interaction with the lump of rough in his hand.

Miller offers his own reasons: "Faceting satisfies my craving for precision and order, both of which are reflected in my professional qualifications. Engineering involves precision and archaeology involves trying to create ordered knowledge from the garbage left behind by previous generations. Geology again gives me a solid grounding in crystallography. In a very real sense, faceting draws all my interests together and provides a creative avenue to compliment my professional career in analytical academic research."

If it is that easy to cut a gemstone, surely it must be as easy to create new designs? Not so. In the case of The Southern Cross Cut, it was back to the drawing board more than once.

What started out as a walk on the beach, doodling patterns in the sand, led to the playing around of something symmetrical in outline with a-symmetrical patterns. An idea of a new rectangular gemstone design took shape and back home in his studio Miller tried to cut the design. However, he soon discovered that to shape the centre diagonal keel was very difficult as there were just too many facets.

"Well, as with all things, before you try something complicated, you should try something simple. So, I had another look at my design and started working with square symmetry and fewer facets arranged in an elongated fan pattern."

The second design worked very well creating a cut that can only be termed elegant simplicity.

"What about the name," I asked. "Is there a story behind that too?"

"Yes, there is. I felt the name should give credit to the southern hemisphere as gem cutting designs have always been dominated by the northern hemisphere craft people. As my design originated in the southern hemisphere and the crossing over of facets creates a perfect cross in the centre of the stone and our famous star constellation, used since antiquity for navigation, is called the southern cross, I thought there could be no other more appropriate name but The Southern Cross Cut."

And so a new gem star is born. The Southern Cross Cut is now an officially registered design and the finished pieces are available directly from the designer/gem cutter Duncan Miller at dmiller@beattie.uct.ac.za.

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