Getting the most out of gemstones

Jun 25, 2009
Dr. Anton Winterfeld and Dr. Peter Klein are getting the most out of gemstones. Credit: Fraunhofer/Dirk Mahler

Emeralds, rubies and the like are referred to as colored gemstones by experts. They sparkle and shine with varying intensity, depending on the cut. A new machine can achieve the best possible cut and extract up to 30 percent more precious stone from the raw material.

"We were astounded when our customer, Markus Wild, approached us and we were not at all certain whether mathematics could offer a solution for the very complex problem of volume optimization of gemstones," says Dr. Anton Winterfeld from the Fraunhofer Institute for Industrial Mathematics ITWM. Jointly with his colleague Dr. Peter Klein, he will receive one of the 2009 Joseph von Fraunhofer prizes for the development of GemOpt, a new industrial process for the volume-optimized utilization of colored gemstones.

In contrast to diamonds, there are innumerable combinations of types and proportions of cut, and types of facet patterns for colored gemstones. When chosen correctly, the interplay of these variables ensures the luster in the stone, its shine. Sometimes just a few facets are sufficient to make a gemstone sparkle, sometimes several hundred. The task was to set limits on what seemed to be infinite and to calculate the optimal volume.

The , which finally resulted in a solution, originated from the area of general semi-infinite optimization. This involved a new type of algorithm, which had until now only been theoretically defined. The team at the ITWM continued to develop this approach and implemented it for this specific problem. The result is an outstanding achievement, also in scientific terms. The second essential part of GemOpt is process control, which Dr. Peter Klein has worked out. For this he ascertained precisely how raw gemstones behave when processed and transferred his findings to the control unit of the machine.

The machine runs fully automatically. First of all, the raw stone is measured. On the basis of these data, the computer calculates optimal embedments, proportions and facet patterns for different basic geometries. The customer then opts for one of the proposed solutions and the machine begins cutting. The process control unit is finely balanced, so that the machine does not split the stones as it cuts them. The system then moves seamlessly on to the polishing step. The 17 axes ensure that the stone can move along any desired path. The machine cuts the facets to ten micrometers exactly - the stones are therefore perfectly geometric. A further advantage is that the machine can produce identical stones - ideal for necklaces. Cutting with the machine can result in up to 30 per cent more weight. This puts a significantly higher price on the stone.

Source: Fraunhofer-Gesellschaft (news : web)

Explore further: ESA investigates an alternative, environmental-friendly method of corrosion resistance

add to favorites email to friend print save as pdf

Related Stories

Writing patterns, logos and lettering in light

Oct 01, 2008

(PhysOrg.com) -- Logos and lettering can be written in light using freeform lenses. But how does the surface of the lens have to be structured in order to focus the light in the shape of a specific pattern? ...

Turbulent fibers

Aug 17, 2006

From car interiors to diapers – non-woven tissues are used every-where. Manufacturers are aiming to produce increasingly hard-wearing non-woven tissues from as little plastic as possible. A simulation model ...

Hope Diamond's phosphorescence key to fingerprinting

Jan 07, 2008

Shine a white light on the Hope Diamond and it will dazzle you with the brilliance of an amazing blue diamond. Shine an ultraviolet light on the Hope Diamond and the gem will glow red-orange for about five ...

Goodbye to batteries and power sockets

Jun 03, 2008

A broken cable or a soiled connector? If a machine in a factory goes on strike, it could be for any of a thousand reasons. Self-sufficient sensors that provide their own power supply will soon make these machines ...

Chimps used tools as early as the Stone Age: study

Feb 12, 2007

Chimpanzees from West Africa were cracking nuts open using stone tools in prehistoric times, according to a study released Monday that suggests some chimp populations may have been using this kind of tool technology ...

Prototyping with industrial robots

Nov 10, 2008

Ship's propellers, parts for wind energy converters, turbine housings – such large-volume castings can only be produced with special molds. The procedure is elaborate and cost-intensive because foundry workers ...

Recommended for you

The oscillator that could makeover the mechanical watch

20 hours ago

For the first time in 200 years the heart of the mechanical watch has been reinvented, thereby improving precision and autonomy while making the watch completely silent. EPFL researchers have developed an ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Arkaleus
not rated yet Jun 25, 2009
This ia great invention, but the price of a stone isn't merely dtermined by carat weight. Price is largely driven by clarity, color, and scarcity. A machine like this may create stones that are larger, but they have more inclusions.

What this may do is actually lower the price of finished stones because the old method of gemcuting was very labor intensive, so much so that most gems are now cut in Asia and shipped overseas.