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Encyclopedia > Diamond cutting

Part of the series on Diamond This article is about the gemstone. ...


Material
Material properties
Crystallographic defects
Formation and surfacing
The 4 Cs
Carat · Clarity
Color · Cut
Production

List of mines
Diamond cutting
The diamond industry
De Beers Description: Diamonds Info: Photographed by Mario Sarto on February 4, 2004 License: GNU Free Documentation License File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... This article addresses the material properties of diamond. ... This article addresses the possible defects of a diamond crystal. ... This article is about the gemstone. ... The carat is a unit of mass used for gems, and equals 200 milligrams or 3. ... Diamond clarity is a quality of diamonds relating to the existence and visual appearance of internal defects of a diamond called inclusions, and surface defects called blemishes. ... Jewelers diamonds in groups of similar colors. ... In order to best utilize a diamond gemstones superlative material properties, a number of different diamond cuts have been developed. ... There are a limited number of commercially viable diamond mines currently operating in the world. ... This article is about the gemstone. ... De Beers, founded in South Africa by Cecil Rhodes, comprises companies involved in rough diamond exploration, diamond mining and diamond trading. ...

Cultural impact
History · Symbolism
Famous diamonds
Imitations and enhancements
Synthetics · Simulants
Enhancements
See also
Index of related articles
Wikipedia Commons media
Man powered Diamond cutting mill in 18th century
Man powered Diamond cutting mill in 18th century

Diamond cutting is the art, skill and, increasingly, science of changing a diamond from a rough stone into a faceted gem. Diamond cutting requires specialized knowledge, tools, equipment, and techniques because of its extreme hardness. As a gemstone, diamond is perhaps the most valued. ... A number of large or extraordinarily colored diamonds have gained fame, both as exquisite examples of the beautiful nature of diamonds, and because of the famous people who wore, bought, and sold them. ... A colourless synthetic diamond produced via chemical vapour deposition Synthetic diamond is diamond produced through chemical or physical processes in a factory. ... Due to its low cost and close visual likeness to diamond, cubic zirconia has remained the most gemologically and economically important diamond simulant since 1976. ... This article addresses treatments designed to enhance the gemological characteristics of diamond. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... As a gemstone, diamond is perhaps the most valued. ... Facets are flat faces on geometric shapes. ...


'Cut' has two meanings in relation to diamonds. The first is the shape: round, oval and so on. The second relates to the specific quality of cut within the shape, and the quality and price will vary greatly based on the cut quality. Since diamonds are very hard to cut, special diamond bladed edges are used to cut them.

Contents

Diamond cutting process

The diamond cutting process includes these steps; planning, cleaving or sawing, bruting, polishing, and final inspection.[1]


Planning

Diamond manufacturers analyse diamond rough from an economic perspective, with two objectives steering decisions made about how a faceted diamond will be cut. The first objective is that of maximum return on investment for the piece of diamond rough. The second is how quickly the finished diamond can be sold. Scanning devices are used to get 3-dimensional computer model of the rough stone. Also, inclusions are photographed and placed on the 3D model, which is then used to find an optimal way to cut the stone. In finance, the return on investment (ROI) or just return is a calculation used to determine whether a proposed investment is wise, and how well it will repay the investor. ...


Maximizing Value

The process of maximising the value of finished diamonds, from a rough diamond into a polished gemstone, is both an art and a science. The choice of cut is influenced by many factors. Market factors include the exponential increase in value of diamonds as weight increases, referred to as weight retention, and the popularity of certain shapes amongst consumers. Physical factors include the original shape of the rough stone, and location of the inclusions and flaws to be eliminated.


Weight retention

The weight retention analysis studies the diamond rough to find the best combination of finished stones as it relates to per carat value. For instance a 2.20 carat (440 mg) octahedron may produce either two half carat (100 mg) diamonds whose combined value may be higher than that of a 0.80 carat (160 mg) diamond and 0.30 carat (60 mg) diamond that could be cut from the same rough diamond.


The round brilliant cut and square brilliant cuts are preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly shaped crystals, such as macles are more likely to be cut in a fancy cut—that is, a cut other than the round brilliant—which the particular crystal shape lends itself to.

An uncut diamond does not show its prized optical properties
An uncut diamond does not show its prized optical properties

Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight; rarely is it less than 50%.[citation needed] Sometimes the cutters compromise and accept lesser proportions and symmetry in order to avoid inclusions or to preserve the weight. Since the per-carat price of a diamond shifts around key milestones (such as 1.00 carat), many one-carat (200 mg) diamonds are the result of compromising Cut quality for Carat weight. Some jewelry experts advise consumers to buy a 0.99 carat (198 mg) diamond for its better price or buy a 1.10 carat (220 mg) diamond for its better cut, avoiding a 1.00 carat (200 mg) diamond, which is more likely to be a poorly cut stone. Image File history File links Download high resolution version (651x618, 259 KB) Yellow diamond Origin: This picture was taken at a diamond exposition in Paris, 2001, France Description = rough octaedral cristal (2x2 cm) Source = the author is owner Date = created 2001 Author = Eurico Zimbres FGEL/UERJ Permission = Free for all... Image File history File links Download high resolution version (651x618, 259 KB) Yellow diamond Origin: This picture was taken at a diamond exposition in Paris, 2001, France Description = rough octaedral cristal (2x2 cm) Source = the author is owner Date = created 2001 Author = Eurico Zimbres FGEL/UERJ Permission = Free for all...


Color retention

In colored diamonds, cutting can influence the color grade of the diamond, thereby raising its value. Certain cut shapes are used to intensify the color of the diamond. The radiant cut is an example of this type of cut.


Natural green color diamonds most often have merely a surface coloration caused by natural irradiation, which does not extend through the stone. For this reason green diamonds are cut with significant portions of the original rough diamond's surface (naturals) left on the finished gem. It is these naturals that provide the color to the diamond.


Turnaround minimization

The other consideration of diamond planning is how quickly a diamond will sell. This consideration is often unique to the type of manufacturer. While a certain cutting plan may yield a better value, a different plan may yield diamonds that will sell sooner, and thereby returning the investment sooner.


Cleaving or sawing

Cleaving is the separation of a piece of diamond rough into separate pieces, to be finished as separate gems.


Sawing is the usage of a diamond saw or laser to cut the diamond rough into separate pieces.


Bruting

Bruting is the process whereby two diamonds are set onto spinning axles turning in opposite directions, which are then set to grind against each other to shape each diamond into a round shape. This can also be known as girdling.


Polishing

Polishing is the name given to process whereby the facets are cut onto the diamond and final polishing is performed. The process takes the steps blocking, faceting, and polishing.


Final inspection

The final stage involves thoroughly cleaning the diamond in acids, and examining the diamond to see whether it meets the quality standards of the manufacturer.


Cutting process

It is possible only because the hardness of diamond varies widely according to the direction in which one is trying to cut or grind. This article or section does not cite any references or sources. ... This article is about the gemstone. ...


A simplified round brilliant cut process includes the following stages: A scattering of brilliant cut diamonds shows off the many reflecting facets. ...

  • Sawing the rough stone.
  • Table setting where one facet is created. The table facet is then used to attach the stone into a dop.
  • Bruting the girdle.
  • Blocking 4 main pavilion facets.
  • Transferring to another dop. This is done to rotate the stone.
  • Blocking 4 main crown facets.
  • Cutting and polishing all pavilion facets.
  • Transferring to another dop.
  • Cutting and polishing all crown facets.

This is just one, although fairly common way of creating a round brilliant cut. The actual process also includes many more stages depending on the size and quality of the rough. For example, bigger stones are first scanned to get the 3-dimensional shape, which is then used to find the optimal usage. The scanning may be repeated after each stage and bruting may be done in several steps, each bringing the girdle closer to the final shape.


See also

This article is about the gemstone. ... In order to best utilize a diamond gemstones superlative material properties, a number of different diamond cuts have been developed. ...

External links

  • Diamond Design, Marcel Tolkowsky. Web edition as edited by Jasper Paulsen.
  • Mining Diamond News

References

  1. ^ Diamonds and Diamond Grading: The Evolution of Diamond Cutting Gemological Institute of America, Carlsbad, California, 2002

  Results from FactBites:
 
Diamond Wire Technology, LLC - Cutting with Diamond Wire (854 words)
Cutting with diamond wire should be considered when there is a need for cutting composites of dissimilar materials, because the gentle cutting action of diamond wire does not smear one material into another and does not snag at the border between two materials.
Because cutting with diamond wire is a gentle cutting process, and the diamonds used for cutting are micron sized, diamond wire cutting is generally a slow process compared to other cutting methods.
Cutting with a diamond wire saw generates very little heat because of the size of the diamonds doing the work, and the controlled cutting force that is applied.
Manufacturing the Diamond | How Diamonds are Manufactured (692 words)
The decision to cut a diamond in a particular shape is dictated by the natural shape of the rough stone.
Diamond cutting has been a work in progress since the first diamonds were cut in the mid 1300s.
Cuts have evolved from the first and most simplistic point cut - a basic four-sided cut that resembles the outline of rough octahedral crystals - to the table cut, single cut, old mine cut, old European cut and finally the modern brilliant cut.
  More results at FactBites »

 
 

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