Because of the nature of the sporadic supply and high cost of the rough, emerald cutting in Colombia is a small family business.There is hundreds of small cutting operations. No big cutting factories exist in Colombia. The cutting method basically has not changed in centuries.
The fashioning process, starts by sawing the rough into pieces, then in a grinding wheel.The rough is pre-formed to comply to the final shape desired. This is the most critical part of the process. This is were the money is. A wise decision and good luck can yield extraordinary results.
Once the rough has been performed, a flat surface is polished, so that the stone can be "stuck" to the "peg" with a parallel face and good precision. Here the cutter is heating the wax that will stick the stone to the "peg".
The stone is being aligned with the use of a device that lies the stone parallel to the surface and the peg perpendicular to the face. This proper alignment is necessary to obtain good symmetry.
With the aid of this arm, the cutter selects the angles necessary to create the desired cut, by lowering the peg to the running disk, the grinding and polishing are accomplished.
Continuous loupe examination is necessary to control the shape and facet junctions. Good faceting aims at a proper balance, total symmetry and perfect facet junctions and surface polish. Once the faceting is done, the wheel is changed to a lesser grit for polishing. A variety of compounds are employed in this process to help attain the highest degree of surface polish.
The main consideration in cutting emeralds is to obtain the best exposure of their magical green color. Faceting adds brilliance and spark, enhancing the beauty of these stones. Though, emeralds have not always been cut in facets. In early civilizations emeralds were cut and polished cabochon style, hemispherical form in which the flat surface was attached to the ornament or jewel.
In spite of the fact that gem cutting is an art almost 5000 years old, it was not until the Middle Ages that cutters began to use facets or flat surfaces for transparent stones. They discovered that when cutting a series of flat surfaces on the underside and the top of a transparent gemstone, the bottom facets acted as mirrors reflecting light and thus giving the stone a superior brilliance.
The classical 'emerald cut' developed in the 17th century consists of sixteen facets in the upper surface of the stone, or crown, and twenty in the pavilion below. Modern jewelry uses round, pear and oval shapes in addition to other free forms of faceting.
For the experienced cutter, the inclusions present in most emeralds, which might disperse light and flatten color and brilliance, are opportunities to enhance the final cut gem. Just as fingerprints, these 'gardens' identify an emerald's origins and make it impossible to fake the gemstone. Only after the talented cutter has thoroughly studied the rough crystal against strong light from every angle, does he begin the cutting process, which exposes the gem's hidden luster, thus transforming it into a glittering jewel.