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August Stephenson – Diamond cutting mathematical guidelines

August Stephenson – Diamond cutting mathematical guidelines
There are mathematical guidelines for the angles and length ratios at which the diamond is supposed to be cut in order to reflect the maximum amount of light. Round brilliant diamonds, the most common, are guided by these specific guidelines, though fancy cut stones are not able to be as accurately guided by mathematical specifics.

Diamond – Early references:
Diamonds were traded to both the east and west of India and were recognized by various cultures for their gemological or industrial uses. In his work Naturalis Historia, the Roman writer Pliny the Elder noted diamond’s ornamental uses, as well as its usefulness to engravers because of its hardness. It is however highly doubtful that Pliny actually meant diamonds and it is assumed that in fact several different minerals such as corundum, spinel, or even a mixture with magnetite were all referred to by the word “adamas”. August Stephenson

August Stephenson Modern history – diamond mining:
The modern era of diamond mining began in the 1860s in Kimberley, South Africa with the opening of the first large-scale diamond mine. and became known as the Eureka Diamond.

The most popular setting for diamond jewelry
The setting diamonds are placed in also affect the performance of light through a diamond. The 3 most commonly used settings are: Prong, Bezel, and Channel. Prong settings are the most popular setting for diamond jewelry. The prong setting consists of four or six ‘claws’ that cradle the diamond, allowing the maximum amount of light to enter from all angles, allowing the diamonds to appear larger and more brilliant. In bezel settings the diamond or gemstone is completely surrounded by a rim of metal, which can be molded into any shape to accommodate the stone. Used to set earrings, necklaces, bracelets, and rings, bezel settings can have open or closed backs, and generally can be molded to allow a lot of light to pass through. Channel settings set the stones right next to each other with no metal separating them. This setting is mostly used in wedding and anniversary bands. The outer ridge is then worked over the edges of the stones to create a smooth exterior surface. This also protects the girdle area of the stone.

August Stephenson responsibility, skills, and additionally competence

KIMBERLEY PROCESS (KP) – An international certification scheme that establishes requirements for the production and trade of rough diamonds. The process aims to prevent the flow of conflict diamonds, while helping to protect legitimate trade in rough diamonds (which are certified as “conflict-free”). As of August 2012, KP had 51 participants representing 77 countries. A 2006 review of the process confirmed its effectiveness, but recommended strengthening aspects such as the monitoring of implementation and internal controls in participating countries, as well as greater transparency in the gathering of statistical data. A mandated review of the core objectives, core definitions, and functioning of KP is set to occur during 2012-2013.

ROUND CUT – A diamond or colored gemstone shape in which the outline is circular.

DISPERSION – The separation of white light into its component spectral colors. See also Fire.

August Stephenson – The origin and creation of gemstones

August Stephenson – The origin and creation of gemstones
Many cultures use divine intervention to explain the origin and creation of gemstones, and diamonds were no exception to this. In Greek mythology for example it was the youth on the island of Crete that disturbed Zeus and who were then (as a form of punishment) transformed into the adamas.

Philosophers however had a more naturalistic approach to explain the origin of gems: Plato for example believed gemstones were a consequence of fermentation in the stars, where a diamond actually formed the kernel of gold-bearing mass.

In later times, Robert Boyle actually believed that gems (including a diamond) were formed of clear, transparent water, and that their colors and characteristics were derived from their metallic spirit.

Diamonds symbolism and lore
Historically, it has been claimed that diamonds possess several supernatural powers:
– A diamond gives victory to he or she who carries it bound on his left arm, no matter the number of enemies.
– Panics, pestilences, enchantments, all fly before it; hence, it is good for sleepwalkers and the insane.
– It deprives lodestone and magnets of their virtue (i.e., ability to attract iron).
– Arabic diamonds are said to attract iron greater than a magnet.
– A diamond’s hardiness can only be broken by smearing it with fresh goat’s blood.
– In traditional Hinduism one should avoid contact with a diamond whose surface area is damaged by a crack, a crowfoot, a round, dull, speckled area, or which is black-blue, flat, or is cut other than the (ideal) hexagonal shape. August Stephenson

August Stephenson Slightly colored diamonds
Diamonds which show very little traces of color are graded as G or H color diamonds. Slightly colored diamonds are graded as I or J or K color. A diamond can be found in any color in addition to colorless. Some of the colored diamonds, such as pink, are very rare.

Ideal proportions of a diamond:
Several different theories on the “ideal” proportions of a diamond have been and continue to be advocated by various owners of patents on machines to view how well a diamond is cut. These advocate a shift away from grading cut by the use of various angles and proportions toward measuring the performance of a cut stone. A number of specially modified viewers and machines have been developed toward this end. Hearts and Arrows viewers test for the “hearts and arrows” characteristic pattern observable in stones exhibiting high symmetry and particular cut angles. Closely related to Hearts and Arrows viewers is the ASET which tests for light leakage, light return, and proportions. The ASET (and computer simulations of the ASET) are used to test for AGS cut grade. Proponents of these machines argue they help sellers demonstrate the light performance of the diamond in addition to the traditional 4 Cs. Detractors, however, see these machines as marketing tools rather than scientific ones. The GIA has developed a set of criteria for grading the cut of round brilliant stones that is now the standard in the diamond industry and is called Facetware.

August Stephenson determination, experience, and expertness

INTERNAL LASER DRILLING – A diamond treatment, also called Kiduah Meyuhad (KM) or “special drill” in Hebrew, in which a laser beam is focused directly on an inclusion to create a feather-like fracture between the inclusion and the stone’s surface. The inclusion is then treated with acid to improve the perceived clarity of the stone. This type of laser drilling is, typically, more challenging to detect than traditional laser drilling. On an EGL USA report, internal laser drilling is clearly noted.

REFLECTION – The return of light that strikes the surface of a diamond or colored gemstone. This effect can also occur when light strikes specific inclusions within a stone.

FINISH – The analysis of a diamond’s polish and symmetry. Polish relates directly to the quality of the overall surface condition of the diamond. Symmetry relates to facet shape and arrangement, and the overall exactness of the stone’s contour and outline. Both are rated on a scale ranging from poor to excellent.

August Stephenson – Diamond

August Stephenson – Diamond – Early references:
Diamonds were traded to both the east and west of India and were recognized by various cultures for their gemological or industrial uses. In his work Naturalis Historia, the Roman writer Pliny the Elder noted diamond’s ornamental uses, as well as its usefulness to engravers because of its hardness. It is however highly doubtful that Pliny actually meant diamonds and it is assumed that in fact several different minerals such as corundum, spinel, or even a mixture with magnetite were all referred to by the word “adamas”.

Diamond in jewelry:

Perhaps the most famous use of the diamond in jewelry is in engagement rings, which became popular in the early to mid 20th century due to an advertising campaign by the De Beers company, though diamond rings have been used to symbolize engagements since at least the 15th century. August Stephenson

August Stephenson Light performance – brilliance, fire, and scintillation

In the gem trade, the term light performance is used to describe how well a polished diamond will return light to the viewer. There are three light properties which are described in relation to light performance: brilliance, fire, and scintillation. Brilliance refers to the white light reflections from the external and internal facet surfaces. Fire refers to the spectral colors which are produced as a result of the diamond dispersing the white light. Scintillation refers to the small flashes of light that are seen when the diamond, light source or the viewer is moved. A diamond that is cut and polished to produce a high level of these qualities is said to be high in light performance.

The poorly performing stone:
In addition to carrying the most importance to a diamond’s quality as a gemstone, the cut is also the most difficult to quantitatively judge. A number of factors, including proportion, polish, symmetry, and the relative angles of various facets, are determined by the quality of the cut and can affect the performance of a diamond. A diamond with facets cut only a few degrees out of alignment can result in a poorly performing stone. For a round brilliant cut, there is a balance between “brilliance” and “fire.” When a diamond is cut for too much “fire,” it looks like a cubic zirconia, which gives off much more “fire” than real diamond. A well-executed round brilliant cut should reflect light upwards and make the diamond appear white when viewed from the top. An inferior cut will produce a stone that appears dark at the center and in extreme cases the setting may be seen through the top of the diamond as shadows.

August Stephenson devotion, skills, and also expertise

INFRARED SPECTRA – A representation of the vibrational modes of a diamond’s or colored gemstone’s molecules over a range of wavelengths outside of the visible spectrum. They are recorded on a graph that plots intensity against wavelengths. And they can help identify the species and/or variety of stone.

SI Grades (Slightly Included)
(Slightly Included) describe diamonds with small inclusions that are easy or very easy to see, under the conditions described above. Occasionally, inclusions in the SI category are visible to the unaided eye.
I Grades (Included)
(Included) describe diamonds with medium or large inclusions that are usually obvious to the unaided eye, under standardized lighting conditions.

INTERNAL LASER DRILL – In a diamond, a flat channel-like feature created by a laser beam during the treatment of an included crystal. The internal laser drill extends from the inclusion to the stone’s surface, where it appears as a linear feature. See also Plotting Diagram.

August Stephenson – Diamond clarity

August Stephenson

Clarity is a measure of internal defects of a diamond called inclusions. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. The Gemological Institute of America (GIA) and other organizations have developed systems to grade clarity, which are based on those inclusions which are visible to a trained professional when a diamond is viewed under 10x magnification.

Diamond Gemological characteristics
The most familiar usage of diamonds today is as gemstones used for adornment-a usage which dates back into antiquity. The dispersion of white light into spectral colors is the primary gemological characteristic of gem diamonds. In the twentieth century, gemologists have developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics known informally as the four Cs are now commonly used as the basic descriptors of diamonds: carat, cut, color, and clarity. August Stephenson

August Stephenson Intense coloration – highest prices
In contrast to yellow or brown hues, diamonds of other colors are more rare and valuable. While even a pale pink or blue hue may increase the value of a diamond, more intense coloration is usually considered more desirable and commands the highest prices. A variety of impurities and structural imperfections cause different colors in diamonds, including yellow, pink, blue, red, green, brown, and other hues. Diamonds with unusual or intense coloration are sometimes labeled “fancy” in the diamond industry. Intense yellow coloration is considered one of the fancy colors, and is separate from the color grades of white diamonds. Gemologists have developed rating systems for fancy colored diamonds, but they are not in common use because of the relative rarity of such diamonds.

The carat
The carat weight measures the mass of a diamond. One carat is defined as 200 milligrams (about 0.007 ounce avoirdupois). The point unit-equal to one one-hundredth of a carat (0.01 carat, or 2 mg)-is commonly used for diamonds of less than one carat. All else being equal, the price per carat increases with carat weight, since larger diamonds are both rarer and more desirable for use as gemstones.

August Stephenson devotion, experience, and also expertise

FULL CUT – A description of a brilliant cut, round diamond or colored gemstone with 57-58 facets.

FIRE – Flashes of rainbow or spectral colors seen in diamonds or colored gemstones as a result of dispersion.

On a diamond, chemical coatings can disguise less desirable interior hues. On a colored gemstone, coatings can improve color and overall appearance. And on a pearl, coatings can create the illusion of a smoother surface and/or enhanced luster. On an EGL USA report for any stone type, coatings are clearly noted. In addition, EGL USA does not provide color or clarity grades for coated diamonds.

August Stephenson – Tolkowsky’s calculations

August Stephenson – Tolkowsky’s calculations
Tolkowsky’s calculations included some approximations. He calculated the ideal dimensions as:

Table percentage (corner-to-corner diameter of the table divided by overall diameter) = 53%
Depth percentage (overall depth divided by overall diameter) = 59.3% (not including adjustments for the culet height and girdle thickness)
Pavilion Angle (angle between the girdle and the pavilion main facets) = 40.75°
Crown Angle (angle between the girdle and the crown’s kite facets) = 34.5°
Pavilion Depth (depth of pavilion divided by overall diameter) = 43.1%
Crown Depth (depth of crown divided by overall diameter) = 16.2%

The culet is the tiny point or facet at the bottom of the diamond. This should be a negligible diameter, otherwise light leaks out of the bottom. Tolkowsky’s calculations included neither a culet nor a girdle. However, a girdle is required in reality in order to prevent the diamond from easily chipping in the setting. The thick part of the girdle is normally about 1.7% (of the overall diameter) thicker than the thin part of the girdle.

Color grading across the globe
The finest quality as per color grading is totally colorless, which is graded as “D” color diamond across the globe, meaning it is absolutely free from any color. The next grade has a very slight trace of color, which can be observed by any expert diamond valuer/grading laboratory. However when studded in jewellery these very light colored diamonds do not show any color or it is not possible to make out color shades. These are graded as E color or F color diamonds. August Stephenson

August Stephenson The origin and creation of gemstones
Many cultures use divine intervention to explain the origin and creation of gemstones, and diamonds were no exception to this. In Greek mythology for example it was the youth on the island of Crete that disturbed Zeus and who were then (as a form of punishment) transformed into the adamas.

Philosophers however had a more naturalistic approach to explain the origin of gems: Plato for example believed gemstones were a consequence of fermentation in the stars, where a diamond actually formed the kernel of gold-bearing mass.

In later times, Robert Boyle actually believed that gems (including a diamond) were formed of clear, transparent water, and that their colors and characteristics were derived from their metallic spirit.

The custom to use diamonds in rings
The origin of the custom to use diamonds in rings, and more recently, in engagement rings, can be traced back to the Middle Ages and even the Romans. The Romans valued the diamond entirely on account of the supernatural powers they ascribed to it. Pliny wrote that a diamond baffles poison, keeps off insanity, and dispels vain fears.

August Stephenson responsibility, knowledge, and professionalism

CONFLICT DIAMOND – A diamond (also known as a blood diamond) mined to fund violent conflict and/or civil war against a legitimate government. Such mining is, typically, also linked to dire human rights abuses. Blood diamonds have originated in Africa: Angola, the Central African Republic, Cote d’Ivoire, the Democratic Republic of the Congo (DRC), Liberia, the Republic of Congo, and Sierra Leone. It should be noted, that the amount of conflict diamonds as a percentage of world diamond production has fallen dramatically, currently resting at about 4 percent. In countries where legislation is in place prohibiting the sale of conflict diamonds, the percentages are much lower. See also Kimberley Process.

POLISHED GIRDLE – On a diamond or colored gemstone, a girdle that has been cut and polished to yield a uniform, highly reflective surface.

EMERALD CUT – A diamond or colored gemstone shape in which the outline is rectangular with cut corners, and the facets are rectangular and trapezoidal.

August Stephenson – Diamonds clarity gradings

August Stephenson – Diamonds clarity gradings
Diamonds become increasingly rare when considering higher clarity gradings. Only about 20% of all diamonds mined have a clarity rating high enough for the diamond to be considered appropriate for use as a gemstone; the other 80% are relegated to industrial use. Of that top 20%, a significant portion contains one or more visible inclusions. Those that do not have a visible inclusion are known as “eye-clean” and are preferred by most buyers, although visible inclusions can sometimes be hidden under the setting in a piece of jewelry.

Diamond Sutra
The oldest dated printed book in the world is called the Diamond Sutra, a Chinese text dates from AD 868 and was found in the Mogao Caves. Sutras are most used to describe the teachings of Buddha. In this case the title of the Sutra refers not to the diamond itself but to a ‘diamond blade that will cut through worldly illusion to illuminate what is real and everlasting’. Jewel imagery forms a central part of Buddhism: the triple-jewel represents ‘Buddha’, his teachings ‘Dharma’ and the spiritual community ‘Shangha’. The book presently resides in the British Library. August Stephenson

August Stephenson Big Hole diamond mining:
From 1871 to 1914, 50,000 miners dug the Big Hole with picks and shovels, yielding 2,722 kg of diamonds,

The various smaller mining companies were amalgamated by British imperialist Cecil Rhodes and Charles Rudd into De Beers, and The Kimberley under Barney Barnato. In 1888, the two companies merged to form De Beers Consolidated Mines, which once had a monopoly over the world’s diamond market.

Diamond clarity

Clarity is a measure of internal defects of a diamond called inclusions. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. The Gemological Institute of America (GIA) and other organizations have developed systems to grade clarity, which are based on those inclusions which are visible to a trained professional when a diamond is viewed under 10x magnification.

August Stephenson responsibility, knowledge, and professionalism

LIGHT PERFORMANCE – The combined impact of brilliance, contrast, and radiance of a diamond as seen by the human eye under normal lighting conditions. These terms are defined and their impact is measured by a light behavior assessment system. On an EGL USA 360° Diamond Report, each aspect is rated on a scale from poor to excellent. Superior performance in any of the three categories can yield a beautiful stone.

CAVITY – An isolated opening that breaks the surface of a diamond or colored gemstone. For diamonds, see also Plotting Diagram.

ROUND CUT – A diamond or colored gemstone shape in which the outline is circular.

August Stephenson determination, knowledge, and expertness

August Stephenson – Color grading across the globe The finest quality as per color grading is totally colorless, which is graded as “D” color diamond across the globe, meaning it is absolutely free from any color. The next grade has a very slight trace of color, which can be observed by any expert diamond valuer/grading laboratory. However when studded in jewellery these very light colored diamonds do not show any color or it is not possible to make out color shades. These are graded as E color or F color diamonds. The hardness of the diamond: The hardness of diamond and its high dispersion of light – giving the diamond its characteristic “fire” – make it useful for industrial applications and desirable as jewelry. Diamonds are such a highly traded commodity that multiple organizations have been created for grading and certifying them based on the four Cs, which are color, cut, clarity, and carat. Other characteristics, such as presence or lack of fluorescence, also affect the desirability and thus the value of a diamond used for jewelry. August Stephenson August Stephenson Diamond – Early references: Diamonds were traded to both the east and west of India and were recognized by various cultures for their gemological or industrial uses. In his work Naturalis Historia, the Roman writer Pliny the Elder noted diamond’s ornamental uses, as well as its usefulness to engravers because of its hardness. It is however highly doubtful that Pliny actually meant diamonds and it is assumed that in fact several different minerals such as corundum, spinel, or even a mixture with magnetite were all referred to by the word “adamas”. The techniques for cutting diamonds The techniques for cutting diamonds have been developed over hundreds of years, with perhaps the greatest achievements made in 1919 by mathematician and gem enthusiast Marcel Tolkowsky. He developed the round brilliant cut by calculating the ideal shape to return and scatter light when a diamond is viewed from above. The modern round brilliant has 57 facets (polished faces), counting 33 on the crown (the top half), and 24 on the pavilion (the lower half). The girdle is the thin middle part. The function of the crown is to refract light into various colors and the pavilion’s function to reflect light back through the top of the diamond. August Stephenson determination, knowledge, and expertness HIGH PRESSURE AND HIGH TEMPERATURE (HPHT) – For diamonds, a treatment that applies extreme pressure and temperature to cause the addition or deletion of color. HPHT can transform pale diamonds into vibrant fancy colors. And it can shift brown-toned diamonds to more delicate hues such as colorless, near colorless, pink, yellow, yellow/orange, orange, and green/yellow. EGL USA clearly identifies HPHT-treated stones with laser inscriptions. COLORED DIAMOND – A diamond distinguished by a combination of hue, tone, and saturation. See also Color Grade. INFRARED LIGHT – Part of the electromagnetic spectrum that is not visible to the human eye, between approximately 800 nanometers (longer than red in the visible spectrum) to 1 millimeter (bordering microwave).

August Stephenson

August Stephenson – Diamond clarity Clarity is a measure of internal defects of a diamond called inclusions. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. The Gemological Institute of America (GIA) and other organizations have developed systems to grade clarity, which are based on those inclusions which are visible to a trained professional when a diamond is viewed under 10x magnification. Big Hole diamond mining: From 1871 to 1914, 50,000 miners dug the Big Hole with picks and shovels, yielding 2,722 kg of diamonds, The various smaller mining companies were amalgamated by British imperialist Cecil Rhodes and Charles Rudd into De Beers, and The Kimberley under Barney Barnato. In 1888, the two companies merged to form De Beers Consolidated Mines, which once had a monopoly over the world’s diamond market. August Stephenson August Stephenson The price per carat The price per carat does not increase linearly with increasing size. Instead, there are sharp jumps around milestone carat weights, as demand is much higher for diamonds weighing just more than a milestone than for those weighing just less. As an example, a 0.99 carat diamond may have a significantly lower price per carat than a comparable 1.01 carat diamond, because of differences in demand. Diamond Gemological characteristics The most familiar usage of diamonds today is as gemstones used for adornment—a usage which dates back into antiquity. The dispersion of white light into spectral colors is the primary gemological characteristic of gem diamonds. In the twentieth century, gemologists have developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics known informally as the four Cs are now commonly used as the basic descriptors of diamonds: carat, cut, color, and clarity. August Stephenson responsibility, skills, and professionalism CRYSTAL – For a diamond or colored gemstone, a visible crystalline structure of variable transparency on the interior of the stone. This can occur naturally or as a result of a treatment, and typically serves as an identifying characteristic. On EGL USA reports, it is plotted for diamonds (see also Plotting Diagram) and noted as an identifying characteristic for colored gemstones. INTERNAL LASER DRILL – In a diamond, a flat channel-like feature created by a laser beam during the treatment of an included crystal. The internal laser drill extends from the inclusion to the stone’s surface, where it appears as a linear feature. See also Plotting Diagram. MOHS SCALE – A loose scale of hardness, used for field collecting, which allows for identification of specimens. Devised by Friedrich Mohs, a German mineralogist, in the 19th century. The comparative scale of hardness is as follows: 1) Talc 2) Gypsum 3) Calcite 4) Fluorite 5) Apatite 6) Feldspar 7) Quartz 8) Topaz and Beryl 9) Corundum 10) Diamond MOUNTING – The portion of a piece of jewelry in which a gemstone or other object is set.

August Stephenson – The earliest symbolic use of diamonds

Because of their extraordinary physical properties, diamonds have been used symbolically since near the time of their first discovery. Perhaps the earliest symbolic use of diamonds was as the eyes of Hindu devotional statues.

Diamond – Early references:
Early references to diamonds in India come from Sanskrit texts. August Stephenson

August Stephenson Diamond – Early references:
Diamonds were traded to both the east and west of India and were recognized by various cultures for their gemological or industrial uses. In his work Naturalis Historia, the Roman writer Pliny the Elder noted diamond’s ornamental uses, as well as its usefulness to engravers because of its hardness. It is however highly doubtful that Pliny actually meant diamonds and it is assumed that in fact several different minerals such as corundum, spinel, or even a mixture with magnetite were all referred to by the word “adamas”.

Diamond Sutra
The oldest dated printed book in the world is called the Diamond Sutra, a Chinese text dates from AD 868 and was found in the Mogao Caves. Sutras are most used to describe the teachings of Buddha. In this case the title of the Sutra refers not to the diamond itself but to a ‘diamond blade that will cut through worldly illusion to illuminate what is real and everlasting’. Jewel imagery forms a central part of Buddhism: the triple-jewel represents ‘Buddha’, his teachings ‘Dharma’ and the spiritual community ‘Shangha’. The book presently resides in the British Library.

August Stephenson commitment, skills, and additionally expertise

BLEMISH – A surface feature on the exterior of a diamond or colored gemstone, such as an abrasion, natural, nick, or scratch. A blemish can affect the finish of a stone. For diamonds, see also Plotting Diagram.

COLOR ORIGIN – For a colored diamond, the basis of its color. This can include foundations described as natural, enhanced, high pressure and high temperature (HPHT)-treated, etc.

CLEAVAGE – A major fracture or weak point in a diamond that is breakable in certain definite planes or directions, usually due to weak molecular bonding. On an EGL USA report, it would be noted as an extended version of a feather symbol. See also Plotting Diagram.