Diamond cut

Introduction and Historical Development of Diamond Cuts

• Diamond cut refers to the style or design guide used when shaping a diamond for polishing.
• The cut of a diamond includes its shape, symmetry, proportioning, and polish.
• The brilliance of a diamond is greatly affected by its cut.
• Different diamond cuts have been developed to maximize the gemstone's properties.
• The round brilliant cut is the most popular, while fancy cuts come in various shapes derived from the round brilliant.
• The practical history of diamond cuts can be traced back to the Middle Ages.
• The theoretical basis for diamond cuts was developed in the early 20th century.
• Design, creation, and innovation in diamond cuts continue to the present day.
• New technology, such as laser cutting and computer-aided design, has revolutionized diamond cutting.
• The modern round brilliant cut has been perfected through mathematical and empirical analysis.
• Diamond cutting in India dates back to the 6th century AD.
• The best form of a diamond was considered to be its natural octahedral crystal form.
• Diamond grinding using lead plate was described in the 11th century AD.
• The diamond could only be polished by other diamonds.
• Some diamonds with ancient Mughal style faceting still exist today.
• Diamond cuts in Europe began in the late Middle Ages.
• Initially, diamonds were used in their natural octahedral state or were polished to create facets.
• The point cut and table cut were early improvements in diamond cutting.
• The old single cut and rose cut were introduced in the 16th century.
• The first brilliant cuts, known as Mazarins, were developed in the 17th century.
• The number of crown facets in brilliant cuts increased over time.
• The old European cut, developed in the 19th century, was the forerunner of modern brilliants.
• American jeweler Henry Dutton Morse opened the first American diamond cutting factory in Boston.
• The old European cut had a shallower pavilion and a more rounded shape.
• Mechanical diamond bruting machines and dimensional gauges were introduced to the diamond industry.

Theory and Polish/Symmetry

• A diamond's appearance is transformed through the process of polishing and creating flat facets.
• Two primary factors considered in diamond cut design are the refractive index (RI) and dispersive power.
• Brilliance, the amount of light reflected back to the viewer, is determined by the diamond's RI.
• Fire, the flashes of spectral colors, is a function of the diamond's dispersion.
• Brilliance can be divided into external brilliance (surface reflection) and internal brilliance (reflection from the rear facets).
• Polish refers to the smoothness of the diamond's facets.
• Symmetry refers to the alignment of the facets.
• Poor polish can result in scratched or dulled facets, affecting the sparkle.
• Surface flaws, such as grain lines, can result from defects in the natural stone.
• Poor symmetry can misdirect light as it enters and exits the diamond.

Choice of Cut

• The choice of diamond cut is influenced by the shape of the rough stone, internal flaws, carat weight preservation, and consumer preferences.
• Most gem-quality diamond crystals are octahedra in their rough state.
• The cutter must consider various variables before proceeding with the cut.
• Fancy cuts are chosen based on the original shape of the rough stone and consumer popularity.
• The location of internal flaws or inclusions also impacts the choice of cut.

Diamond Cutting and Polishing Center

• India is the world's top diamond cutting and polishing center.
• It processes 11 out of 12 diamonds in jewelry worldwide.
• The diamond sector in India employs 1.3 million people.
• It accounts for 14% of India's $80 billion annual exports.
• India's share in the world polished diamond market is 92% by pieces and 55% by value.

Round Brilliant Cut and Fancy Cuts

• Developed around 1900, the round brilliant cut is the most popular cut for diamonds.
• It is considered the best choice for saleability, insurability, and desired optics.
• The round brilliant cut consists of 58 facets (or 57 without the culet).
• Crown has 33 facets, pavilion has 25 facets.
• Hearts and arrows describe the visual effect achieved in a round brilliant cut diamond with perfect symmetry and angles.
• When viewed under a special magnifying viewer, a complete pattern of 8 hearts and 8 arrows can be seen.
• Passion cut is a modification of the round ideal cut, designed to enhance brilliance and mask inclusions.
• Fancy cuts include modified brilliants, step cuts, mixed cuts, and other unique shapes.
• Modified brilliants have the same facet counts and arrangements as round brilliants but in different shapes.
• Step cuts have square or rectangular outlines with rectilinear facets arranged parallel to the girdle.
• Mixed cuts combine aspects of brilliant and step cuts.
• Other fancy cuts include rose cuts and various shapes like triangle, kite, lozenge, trapeze, and obus.

Diamond cut Data Sources