The piece diamond is the style or design guide used when shaping a diamond to polish such a brilliant piece. Cut does not refer to shape (pear, oval), but symmetry, proportions and diamond polish. Diamond pieces greatly affect the brilliance of diamonds; this means if it cut badly, it will be less luminous.
To use the best diamond gemstone properties, a number of different diamond cutting b/bs have been developed. Diamond pieces are a more symmetrical arrangement of aspects, which together modify the shape and appearance of diamond crystals. Diamond cutter should consider several factors, such as the shape and size of the crystal, when selecting pieces. The practical history of diamond cutting can be traced back to the Middle Ages, while their theoretical foundations were not developed until the turn of the 20th century. The design and innovation development continues today: new technologies - especially laser cutting and computer-aided design - have enabled cutting development of complexity, optical performance and waste reduction to date unthinkable.
The most popular diamond cut is modern round brilliant, whose arrangement and proportion of its parts has been enhanced by mathematical and empirical analysis. Also popular are the fancy pieces , which come in many different forms - many of which come from brilliant rounds. Diamond pieces are evaluated by trained grade children, with higher values ​​given to symmetry stones and the proportions best suited to the particular "ideal" used as a benchmark. The most stringent standards are applied to a brilliant round; although the number of aspects has not changed, the proportion is not. Different countries base their deductions with different values: one can talk about American Standard or Scandinavian Standard ( Scan DN ), to deliver but two example.
Video Diamond cut
Histori
The history of diamond cutting can be traced to the late Middle Ages, before the time diamonds used in their natural octahedral state - anhedral (poorly formed) diamonds just are not used in jewelry. The first "improvement" of the natural design involves simple polishing of the octahedral crystal surface to create flawless aspects, or to form the desired octahedral shape of unattractive coarse pieces. This is called the cutting point and comes from the mid-14th century; by 1375 there was a diamond polishing guild in NÃÆ'¼rnberg. By the mid-15th century, the cutoff point was improved: a little less than half of the octahedron would be sawed off, creating pieces of the table . The importance of a culet is also manifest, and some cubed stone may have it. The addition of four angular aspects creates an old cut (or eight old pieces). None of this pruning will reveal what diamonds are valuable for today; strong dispersion or fire . At that time, diamonds were valued mainly because of the apamantine sheen and its superlative hardness; diamonds that are cut off the table will appear black to the eyes, as they did in the painting of that era. For this reason, colored gemstones such as ruby ​​and sapphire are much more popular in the jewelry of that era.
In or about 1476 Lodewyk (Louis) van Berquem, a Flemish polisher from Bruges, introduced the absolute symmetry technique in the disposition of aspects using his own invention device, scaif. He cut the stone in a form known as pendeloque or briolette ; this pear-shaped with rectangular facets on both sides. Around the middle of the 16th century, the rose or rosette was introduced in Antwerp: it also consists of rectangular facets arranged in a symmetrical radiant pattern, but with the bottom of the left flat stone - basically a crown without a pavilion. Many famous ancient Indian diamonds (such as Orloff and Sancy) also have pieces like roses; there are some opinions that Western cutter is influenced by Indian stones, as some of these diamonds may have existed before Western adoption of rosebuds. However, India's "rose pieces" are much less symmetrical because their cutters have a major interest in conserving heavy rust, due to the divine status of diamonds in India. In every event, the cutting of roses continues to evolve, with the depth, number and arrangement of the tweaked aspects.
The first brilliant cuts were introduced in the mid-17th century. Known as Mazarins , they have 17 aspects on the crown (top). They are also called double-cut brilliants because they are seen as a step forward from a single cut. Vincent Peruzzi, the Venetian sculptor, then increased the crown facets number from 17 to 33 ( triple-cut or Peruzzi brilliants), thereby significantly increasing the fire and brilliance of the cutting gems, properties which in Mazarin is much better than in roses. But the Peruzzi-cut diamond, when viewed today, looks very boring compared to modern brilliants. Because the practice of bruting has not yet developed, these initial brilliants are all round or rectangular squares in cross section (not circles). Given the common name pillow - what is known today as old mine wounds - this is common at the beginning of the 18th century. Some time later old European pieces were developed, which had a shallower pavilion, a more rounded shape, and a different arrangement of facets. The old European pieces were the modern and most advanced briliar pioneers used during the 19th century.
Around the year 1900, the development of diamond saws and good jewelry lathe enabled the development of diamond cutting and cutting of modern diamonds, heads among those cutting round brilliantly. In 1919, Marcel Tolkowsky analyzed this piece: his calculations took both the brilliance (the amount of reflected white light) and the fire into consideration, creating a delicate balance between the two. Tolkowsky calculations will serve as the basis for all modifications and standards of brilliant pieces in the future.
The Tolkowsky model of the "ideal" piece is not perfect. The original model serves as a general guideline, and does not explore or explain some aspects of diamond cutting:
Since each aspect has the potential to change the field of light rays, each aspect must be considered in the complete calculation of the path of light. Just as a two-dimensional slice of diamond provides incomplete information about the three-dimensional nature of the behavior of light within the diamond, this two-dimensional slice also provides incomplete information about the behavior of light outside diamond. The diamond panorama is three dimensional. Although diamonds are very symmetrical, light can enter diamonds from different directions and many angles. This factor further highlights the need to re-evaluate Tolkowsky's results, and to recalculate the effect of diamond proportions on aspects of his performance....
Another important point to consider is that Tolkowsky does not follow the reflected ray path more than twice on diamonds. However, we now know that the appearance of a diamond consists of many paths of light that reflect more than twice in the diamond. Again, we can see that Tolkowsky's predictions are helpful in explaining optimal diamond performance, but they are incomplete by current technological standards.
Tolkowsky's guidelines, while revolutionary in their day, are not the definitive solution to the problem of finding the optimal proportion of brilliant round cut diamonds.
In the 1970s, Bruce Harding developed another mathematical model for gem design. Since then, several groups have used computer models and special scopes to design diamond cuts.
The largest diamond cutting and polishing center in the world is India. It processes 11 out of 12 diamonds in jewelry around the world. The sector employs 1.3 million people and accounts for 14% of India's annual export of $ 80 billion. The world polished diamond market share is 92% by cut and 55% of its value.
Maps Diamond cut
Theory
In rough circumstances, the diamond is pretty good in appearance. Most gem gems are found from secondary or alluvial deposits, and such diamonds have a dull and worn surface that is often covered by gummy and opaque skins - compared to "soda washcloths". The action of polishing diamonds and creating flat sides in a symmetrical arrangement brings out the hidden beauty of diamonds in dramatic fashion.
When designing diamond pieces, two major factors are considered. The most important is the refractive index (RI) diamond, which at 2,417 (measured by light of sodium, 589.3 nm), is quite high compared to most other gems. Diamond's RI is responsible for brilliance - the amount of incident light reflected back to the viewer. Also important is the diamond dispersive power - the material's ability to split white light into its relatively high-frequency component spectrum at 0.044 (as measured from the B-G interval). The blurring of spectral colors - known as api - is a function of this dispersion, but, like brilliance, is only visible after cutting.
Brilliance can be divided into definitions of external brilliance and internal brilliance . The first is the light reflected off the stone surface - its luster . Diamond's
Internal brilliance - the percentage of incident light reflected back to the rear viewer (pavilion) aspect - depends on careful consideration of the interface interface angles because they are related to RI diamonds. The goal is to achieve total internal reflection (TIR) ​​by selecting the crown angle and pavilion angle (angle formed by the pavilion facet and girdle plane) such that the reflected light of the incident angle (when reaching the pavilion facet) is outside the diamond's critical angle, or the minimum angle for TIR, 24.4 °. Two observations can be made: if the pavilion is too shallow, the light fills the pavilion aspect in a critical angle, and is biased (ie, lost) through the bottom of the pavilion into the air. If the pavilion is too deep, light is initially reflected outside the critical angle on one side of the pavilion, but fills the opposite side in a critical angle and then refracted out the side of the rock.
The term luster is applied to the amount and arrangement of internal reflections of light; that is, the level of "luster" that is visible when the rock or observer moves. Luster depends on size, number, and symmetry of aspect, as well as on paint quality. Very small stones will look like milk if the flash is too big (because of the limitations of the human eye), whereas larger stones will appear lifeless if the surface is too big or too small.
The diamond fire is determined by the crown's crown and the crown angle of the crown as the top of the stone, above the corset), and the size and number of aspects that make up it. The crown acts as a prism: the light coming out of the stone (after reflection from the sides of the pavilion) must satisfy the crown facet at a large inclination angle from the normal as possible (without exceeding the critical angle) to achieve the greatest outflow or spreading spectral color. The crown height is related to the crown angle, the crown facet size, and the table size (the largest major crown facet): the happy medium is sought in a not-so-small table (which will result in larger crown facets and larger fires at the expense of brilliance ) or too large (which will result in smaller crown facets and little or no fire).
Polish and symmetric
Poles and symmetry are two important aspects of cutting. The polish represents the smoothness of the diamond side, and symmetry refers to the alignment in terms. With a bad paint, the surface of a side can be dull, and can create a fuzzy blur or dull. Often a poorly polished diamond surface will have grain lines that cross the sides. It might also look like it needs to be cleaned up. With poor symmetry, light can be misdirected when entering and leaving the diamond.
Snippet selection
Selection of diamond pieces is often decided by the original form of rough stone, the location of internal defect or inclusion, the preservation of heavy rust, and the popularity of certain forms among consumers. Cutter should consider each variable before continuing.
Most gem-quality diamond crystals are octahedra in rough conditions (see the material properties of diamonds). These crystals are usually cut into round brilliants because it is possible to cut two such stones from one octahedron with minimal weight loss. If the crystal is a flaw or a twin, or if the inclusion is present at an improper location, the diamond is more likely to receive a fancy cut (a piece other than a brilliant round). This is especially true in the case of the macle, ie flat twin octahedron crystals. The rounded brilliants have certain proportions that will result in high weight loss, while the luxurious cuts are usually more flexible in this regard. Sometimes the cutter compromises and receives lower proportions and symmetry to avoid inclusion or to maintain the weight of rust, because the diamond price per carat is much higher when the stone is more than one carat (200 mg).
While brilliant round pieces are considered standard for diamonds, with almost constant shape and proportion, the choice of luxury pieces is strongly influenced by fashion. For example, the cutting of the baguette - which features the diamond luster, white, and clarity but underestimates the flames - is all the rage during the Art Deco period, while the Princess cut mix - which features a flame and the brilliance of diamonds rather than its luster - is now gaining popularity. Pieces of the princess are also popular among diamond cutters: of all the pieces, it consumes the least of the original crystals. Older diamonds cut before ca. 1900 is cut in a "primitive" version of a brilliant modern spin, like cut roses and cut old mines (see Historical section). Although there is a market for antique stones, many are recut to modern briliars to increase their selling power. There is also an increase in demand for diamonds cut in the old style for the purpose of repairing or reproducing antique jewelry.
Diamond size can also be a factor. Very small (& lt; 0.02 karat [4mg]) diamond - known as melÃÆ' Â © e - is usually given a simplified piece (ie, with fewer aspects). This is because the full size of a small size will look like milk to the human eye, because of its inability to finish the stone dispersive fire. In contrast, very large diamonds are usually given luxury pieces with many additional aspects. The conventional conventional spin or fancy pieces can not be improved satisfactorily, so additional aspects are needed to ensure there is no "dead point". Because large diamonds tend not to be installed in jewelry, their deductions are considered for how well they display diamond properties from different directions of view; in the case of a more moderate diamond, the deduction is considered primarily because of its appeal.
The brilliant diamonds that dominate the round are not as trendy as they always are because the market is too full in the last decade of the century. Simultaneously, giving luxury pieces of diamonds as precious gems at a particular celebration becomes part of the tradition. Diamond Heart cut has romantic symbolism so it is a common gift for Valentine's Day or wedding anniversary. The pear diamond looks like a drop of water and is suitable for diamond earrings. The most famous forms are: Princess, Pillow, Heart, Pear, Marquise, Radiant, Asscher cut, Emerald, Oval.
Brilliant spots
Developed ca. 1900,
round brilliant is the most popular piece given for diamonds. Usually this is the best choice in terms of sales, insurability (because of its relatively "safe" shape), and the desired optics.
Number and name of facet
The brilliant modern spin (Figures 1 and 2) consists of 58 facets (or 57 if the culet is excluded); 33 on the crown (the upper half above the middle or the corset of the stone) and 25 in the pavilion (lower lower under the corset)). Girdle can be frozen, polished smooth, or variegated. In the last few decades, most girdles have been equipped; many of which have 32, 64, 80, or 96 aspects; these aspects are excluded from the total number of aspects. Similarly, some diamonds may have little additions to the crown or pavilion created to remove surface imperfections during the diamond cutting process. Depending on the size and location, they can hurt the symmetry of the pieces and are therefore considered during the gradation cuts.
Figure 1 assumes that the "thick part of the corset" is the same thickness at 16 "thick part". It does not consider the effect of the indexed upper layer of the girdle. Figure 2 was adapted from the Tolkowsky book, originally published in 1919. Since 1919, the lower part of the lower corset became longer. As a result, the main side of the pavilion becomes narrower.
Proportion
While the number of standard aspects, the actual proportions - the crown height and corner of the pavilion , and table size - is not universally approved. There are at least six "ideal cuts" that have been designed over the years, but only three are commonly used as a benchmarking tool. Developed by Marcel Tolkowsky in 1919, the American Standard (also known as American Ideal and Tolkowsky Brilliant ) is the benchmark in North America. It comes from a mathematical calculation that takes into account both brilliance and fire. The benchmark in Germany and other European countries is Cut Fine Practical (German: Feinschliff der Praxis , also known as Eppler Cut ), was introduced in 1939. It was developed in Germany by empirical observations and differed only slightly from American Standard. Introduced as part of the Nomenclature of Scandinavian Diamond ( Scan D. N. ) in 1969, Scandinavian Standard is also very slightly different.
Other benchmarks include: Brilliant Ideal (developed in 1929 by Johnson and Roesch), Parker Brilliant (1951), and Eulitz Brilliant (1968 ) The Ideal and Parker brilliants are not used because their proportions produce (by contemporary standards) a very low brilliance. The Eulitz cut is the only other mathematical standard; historically it is also the only benchmark to consider the thickness of the corset. A more modern benchmark is set by an Accredited Gem Appraiser (AGA). Although their standards generally make modern ideal cuts have been criticized for being too strict. A summary of the different benchmarks is given below:
The crown height, depth of the pavilion, and the diameter of the table is the percentage of the total diameter of the corset. Since the pavilion angle (and consequently the depth of the pavilion) is closely related to total internal reflection, it varies between at least between different standards.
The phenomenon of heart and arrow
The term Hearts and Arrows is used to describe the visual effects achieved in brilliant rounded diamonds with perfect symmetry and angles that show the pattern of the Heart & amp; Arrow. When viewed under a special magnifying viewer, the complete and precise visual pattern of 8 hearts is seen looking down through the pavilion, and 8 arrows can be seen when looking at the stone on the position table.
The Passion Cut
Another modification of the Ideal Cut round that retains the basic proportion of its corners is Passion Cut. The design of this piece may be considered the reverse of the Heart and Arrow, as it removes arrows to recapture different light from the diamond center. The gap cuts eight parent pavilions and increases the specially placed total sides from 57 to 81. The piece is designed to enhance the inclusiveness of brilliance and mask.
Potongan Fancy
Even with modern techniques, cutting and polishing of diamond crystals always result in dramatic weight loss; rarely less than 50%. Brilliant round cutting is preferred when the crystal is an octahedron, because often two stones can be cut from one such crystal. The odd-shaped crystals such as macles are more likely to be cut in the fancy pieces (ie, pieces other than brilliant rounds), whose special crystal form is suited to it. The prevalence and selection of particular custom pieces are also influenced by modes; In general, these deductions are not done with the same rigorous standards as the rounded brilliants derived from Tolkowsky. The most luxurious pieces can be grouped into four categories: modified brilliants, cutting steps, mixed cuts, and cutting roses. >.
Modified brilliants
This is the category of luxury pieces that are most desirable, because the brilliant rounds of standards can be effectively modified into various shapes. Since facet aspect and facet counts are the same, modified brilliants are also visible (in terms of brilliance and fire interaction) most similar to round brilliants.
Modified brilliants include marquise or navette (French for "small boat", because it resembles a sailboat hull), heart , triangle trillion (also trillian or trilliant ), oval , and pear or drop > cuts. These are the most commonly modified brilliants; Round diamond was created and introduced by Lazare Kaplan in the 1960s. Usually recorded to have 56 aspects, the diamond weight is estimated by measuring the length and width of the stone. The ratio of 1.33 to 1.66 provides a good traditional range of oval-shaped diamonds. Pear-shaped gems are also known as teardrops due to their resemblance and are regarded as hybrids between marquise pieces and brilliant round diamonds. The stone has one rounded tip while the other end is pointed. Pear diamonds can choose between different lengths and width ratios for ideal pear-shaped diamonds. The length to width ratio between 1.45 and 1.75 is the most common.
Modern cutting technology has enabled the development of increasingly complex and unthinkable forms, such as stars and butterflies. Their proportion is largely a matter of personal preference; However, due to their sharp termination and the fragility of their diamonds, these deductions are more susceptible to accidental damage and therefore may be more difficult to insure.
There are some old brilliant pieces that are modified from an uncertain age which, though no longer widely used, are important for historical purposes. They are all round in outline and modify the brilliant standard round by adding aspects and changing the symmetry, either by dividing standard aspects or by placing new ones in different settings. These cuts include: King and Magna cuts, both developed by the New York City company, with the former having 86 aspects and 12-fold symmetry and the last with 102 aspects and Symmetry 10 fold; Cut High-Light , developed by Belgian cutter M. Westreich, with 16 additional aspects divided equally between the crown and the pavilion; and Princess 144 , was introduced in the 1960s, with 144 facets and 8-fold symmetry. Not to be confused with the cut Princess mix, Princess 144 cuts off living stones with good luster; the additional aspect is cut below the corset rather than divided. The extra care required for these sub-girdle facets benefits the finished stone by reducing corset and bearded irregularities (hairline cracks). Today, with increasing understanding of the dynamics of light and diamond cutting, many companies have developed newly modified brilliant cut diamonds. If properly designed, additional aspects of this modified brilliant rotation can benefit the overall beauty of diamonds, such as in 91 diamonds.
The Dutch company, Gassan, has patented new cuts with 121 aspects.
The Cushion Cut, square or rectangle with rounded corners, is also popular.
Cutting step
Stones that have square or rectangular squares and their facets are straight-line and arranged parallel to the corset known as stone step-cut or trap-cut. These stones often have cut corners, creating emerald cut (after the most common application for emerald gems) with an octagonal line. This is done because the sharp angle is the point of weakness in which the diamond can be split or broken. Instead of a culet, a step-cut stone has a keel that runs the length of the pavilion terminal. Like other luxury-shaped diamonds, emerald-cut diamonds can have varying length to width ratios. The most popular and classic emerald cutting line cuts close to 1.5.
The Asscher Cut, a modified Emerald Cut square, is also popular.
Since both the pavilion and the crown are relatively shallow, stepping stones are generally not very bright and never fiery as brilliant cut stones, but rather highlight the clarity of diamonds (because even the slightest flaw will be very visible), white, and luminous (and because it's a good polish).
Because the current mode for cutting is brilliant and brilliant, the diamond cut step may have little value; a deep enough stone can be cut back into a more popular form. However, the straight line shape of the cut line was very popular in the Art Deco period. The antique jewelry of the day displayed the stones cut out prominently, and there was a market in producing new stones to fix antique jewelry or to reproduce it. The lean, rectangular baguette (is from France, resembling a piece of bread) is and is the most common form of cutting step: today, it is most commonly used as an accent stone to flank larger larger stone rings ( and usually intersting brilliant).
Cutting a square step unbroken corner is known as carrÃÆ'Â © ; they are also characteristic of antique jewelry. They may resemble a cursory "Princess cut" shape, but the lack of fire of the crane and the simpler aspects are typical. They may or may not have a culet. In Western jewelry dated before the emergence of brilliant pieces, very short stones are used as a shiny cover for miniature painting: this is known in the antique trade as a portrait stone. The characteristic of Indian jewelry is diamond lasque, which may be a form of initial step. They are flat rocks with large tables and asymmetrical borders.
Other forms of step cut include triangle (or Trilliant cut ), fly , candy (or trapezium ), and obus forms.
Mixed crop
Mixed blends divides aspects of brilliant pruning (both) and steps: they are intended to combine weight preservation and cutting step dimensions with briliian optical effects. Usually the crown is a brilliant piece and step-cut pavilion. Cutting mixes are all relatively new, with the oldest dating since the 1960s. They have been very commercially successful and are steadily gaining popularity, loosening a brilliant de facto standard footing.
Among the first mixed pieces are pieces of Barion, introduced in 1971. Created by South African diamond cutter Basil Watermeyer and named after himself and his wife Marion, the basic Barion piece is square rectangular or rectangular, with polished and variegated belts. The total number of facets is 62 (not including culet): 25 on crown; 29 in the pavilion; and 8 on the belt. This cut can easily be identified by a typical central cross pattern (as seen through the table) created by aspects of the pavilion, as well as by crescent-shaped features in the pavilion. The same cut is Radiant cut : It differs in a total of 70 aspects. Both the and the Barion pieces are present in a large number of modified forms, with slightly different facet arrangements and combinations.
The most successful mixed cut is Princess cut , first introduced in 1960 by A. Nagy from London. It was originally intended for roughly flat (macles), but has since become quite popular that some gemological labs, such as those from the American Gem Society (AGS), have developed standard Princess cutting standards with such strict standards applied to round brilliants. Its higher fire and brilliance compared to other mixed pieces is one of the reasons for the popularity of Princess Cut, but more importantly is the fact that, of all the diamond cuts, it consumes the least of the original crystals. Another beautiful piece is the Flanders cut, a square that is modified with cut corners, brilliant sides and is currently being cut by the cutter in the Russian Star.
Cutting roses and moguls
Various forms of cut roses have been used since the mid-16th century. As with cutting steps, they come from older types of wounds. The cutting of the base rose has a flat base - that is, it has no pavilion - and has a triangular triangle (usually 12 or 24) up to form a point (no table facet) in a setting with six times the rotation symmetry. The so-called double rose cut is a variation that adds six aspects of the kite on the edge of the base. The classic circular rose pieces are roses; non-circular variations on rose pieces including briolette (oval), Antwerpen rose (hexagonal), and Dutch double rose (resembles two roses) back-to-back). Diamond rust-cut is rarely seen today, except on antique jewelry. Like older styles and cutting steps, there is a demand for the purpose of repairing or reproducing antiques.
Associated with rosebuds, and from the same time, are pieces of mogul , named after the gems of the Great Mogul which is the most famous example of its type. Like classic roses cut, mogul pieces also have no pavilions and table facets, and the crown also consists of rectangular facets that rise to form a point. But in mogul-cut diamonds, rotational symmetry is usually fourfold or eightfold, and eight apical sides are united by two or more additional circles in terms. Modern mogul cuts evolved from previous faceting techniques originally used to disguise the internal deficiencies in very large stones; in modern times this piece has also become rare, but still finds occasional use where it is less important to display the internal clarity of the stone, as with the spirits of De Grisogono black and opaque internals.
Cut gradation
The "Cut" of "4 Cs" is the most difficult part for consumers to judge when choosing a good diamond. This is because some certificates will not show important measurements that affect cuts (such as pavilion angles and crown angles) and will not give a subjective rating of how good the pieces are. The other 3 Cs can be ranked only by rating in each category. It takes a trained eye to assess the quality of diamond pieces, and this task is complicated by the fact that different standards are used in different countries (see brilliant proportions round).
The relationship between the crown angle and the pavilion angle has the greatest effect on the diamond appearance. A slightly steep pavilion corner can be equipped with a shallow crown angle, and otherwise . This exchange has been quantified by independent authors, using various approaches.
Other proportions also affect the display of diamonds:
- Table rate is very significant.
- The length of the lower corset side affects whether the Hearts and arrows can be seen on the rock, under a certain audience.
- Most brilliant rounded diamonds have a corset thickness of approximately equal to 16 "thick parts".
- A girdle called "rigged" has a thicker girdle where the main sides touch the girdle than where the adjacent front girle touches the girdle. These stones are heavier (for a certain diameter, average girdle thickness, crown angle, pavilion angle, and table ratio), and have worse optical performance (the upper corset aspect looks dark in some lighting conditions).
- The "painted" girdle has a thinner girdle where the main sides touch the corset rather than the adjacent upper part of the corset touches the girdle. These stones have a slight leakage of light on the edge of the stone (for given crown angles, pavilion angles, and table ratios).
Several groups have developed diamond cutting assessment standards. They all disagree about which proportion makes the best cut. There are certain proportions that are considered best by two or more groups.
- The AGA standard may be the most stringent in the top quality range. David Atlas developed the AGA standard in the 1990s for all standard diamond shapes.
- The HCA changed several times between 2001 and 2004. In 2004, the HCA score under the two represented excellent cuts. HCA distinguishes between brilliant pieces, Tolkowsky, and fiery.
- The AGS standard was changed in 2005 to better suit the Tolkowsky model and Octonus ray results. The 2005 AGS standard punishes stones with girdles "cheated". They rate from 0 to 10, with ranges corresponding to single descriptive words: Ideal (0), Very Good (1), Very Good (2), Good (3-4), Fair (5-7), Poor (8-10)).
- The GIA began assessing cuts on each assessment report for a brilliant start in 2006 based on their comprehensive study of 20,000 proportions with 70,000 observations of 2,000 diamonds. Single descriptive words are as follows: Very Good, Very Good, Good, Fair, and Poor.
The distance from the eye of the observer to the diamond is important. The 2005 AGS cutting standard is based on a distance of 25 cm (about 10 inches). The 2004 HCA cutting standard is based on a distance of 40 centimeters (about 16 inches).
- Labs around the world use VeriGem ImaGem devices to measure Light Behavior. DGLA in the United States and Mumbai, India, PGGL in the United States and EGL-USA both offer this version of ratings in 2008. DGLA has ranked thousands of diamonds with this promising, direct assessment technology.
- "Brilliancescope" by Gemex is another light-assessment behavioral technology used by many US diamond retailers and cutters and now abroad.
Effect of pieces on other diamond characteristics
During the diamond cutting process, the diamond cutter wants to get the heaviest diamond of rough stone. However, this can come at the cost of lowering the cut grade. If the diamond is too deep, the weight of the rust will increase but result in the loss of brilliance due to light leakage. Diamond cutter must struggle by working on the stones to the best finish shape with the least amount of waste. This strategy depends on the quality of the stone and its final proportion. If two diamonds of the same weight are examined there is a difference in size when viewed from above; arguably the most important view. A well-cut 0.90c diamond can have the same width as a poor 1.00CT diamond. This phenomenon is known as spreading.
Cut also affects the color of the diamond. This is very important when considering a luxurious colored diamond, where a slight shift in color can greatly affect the price of a diamond. The most luxurious colored diamonds are not cut to round the brilliants, because while the brilliant rounds are rewarded for their ability to reflect white light, the most important characteristic in a luxury-colored diamond is its color, not its ability to reflect white light.
See also
- List of gemstones
- Brilliant (diamond cut)
- Cut (gem)
- Clarity of diamond
- Diamond color
- Diamond cutting
- Diamond Improvement
- Diamond simulant
- Famous diamond
- Material properties of diamond
- Phoenix Cut Diamond
- Princess cut off
- Synthetic diamond
References
Further reading
- Antique Jewelry University - History of Diamond Cutting
- Bruton, Eric. (1979). Diamonds , 2nd ed. Chilton Book Co. ISBNÃ, 0-8019-6789-9
- Cipriani, Curzio, Borelli, Alessandro, and Lyman, Kennie (US ed.) (1986). Simon & amp; Schuster's Guide to Gems and Precious Stones, p. 58-68. Simon & amp; Schuster, Inc.; New York, New York. ISBNÃ, 0-671-60430-9
- Malecka, Anna (2017). The naming of Koh-i-Noor and the Origin of Mughal Diamonds, The Journal of Gemmology, no. 4. 38 (8).
- Pagel-Theisen, Verena. (2001). Diamond grading ABC: Manual (issue 9), pp.Ã, 176-268. Rubin & amp; Son n.v.; Antwerp, Belgium. ISBN 3-9800434-6-0 [1]
- OctoNus Software has posted several studies of diamond cuts, by various authors. OctoNus, Moscow State University, Bruce Harding, and others have posted jobs there.
- Holloway, Garry (2000-2004). HCA: defining the ideal cut diamond is a detailed explanation of "Cut Holloway Advisers". Web services using this software are available.
- Blodgett, Troy; et al. (GIA) (2006) "Painting and Digging", GIA 2006 article.
Source of the article : Wikipedia
0 Comments