Tuesday, 22 April 2014

DIAMOND JEWELRY DESIGNING TRAINING INSTITUTE


 Academy of JEWELRY Design

Mobile: +91-9444100081, +91-9840689781

Chennai Jewellery Academy Design School <chennai.jewellerydesignschool@gmail.com>

Land Mark : Prestige Pallidium Bayan,
TVS Kohinoor Showroom and Opp to Chennai Telephones
3rd floor, Eskay Building, Above cool club
Greams Road
Thousand Lights
Chennai - 600006

 seshu.gopal@jewelrydesignacademy.com











  • What is a diamond?
  • Where do diamonds come from?
  • How is a diamond cut?
  • What is an "Ideal Cut"?
  • How does a diamond get from the mines to the stores?
  • Is a diamond a good investment?
  • What is the difference between a "certified diamond" and a "non-certified diamond"?
  • Is it safe to receive a diamond in the mail?
  •  
  •  
 
A diamond is a crystal made up entirely of carbon atoms that are arranged in an isometric, or cubic, matrix. A cubic crystal arrangement is one in which the crystal essentially expands outward at the same rate in all directions during its initial growth; the ideal result, when the crystal forms without any interference, is a pure and perfectly formed octahedral shape. However, most diamond crystals encounter varying heat or pressure, other elements, or even other diamond crystals during their growth, and this can alter their form somewhat. The resulting form and characteristics of the crystal, once it emerges from the earth, help to determine what shape, color and clarity the polished gem will have.
The combination of diamond's molecular composition and its crystal structure is what makes it so unique and gives it all the qualities that we think of when we think of a diamond.
Consider this: The graphite that you commonly find in pencils is also made of pure carbon, but because the carbon atoms are arranged differently, the result is a soft gray-black substance that is very unlike hard, colorless diamond. And iron pyrite (known more commonly as "fool's gold") grows in an isometric arrangement, but because it is not made of pure carbon, it also lacks the spectacular qualities of diamond. 

The unique characteristics of diamond go far beyond what you can see with your eye. In addition to their superior brilliance and dispersion, diamonds are the hardest natural substance on earth. 


Diamond rates a 10 on the Mohs scale of hardness, which means that it is extremely resistant to scratches; it is several times harder than the next-hardest substance, corundum, which is more commonly known as ruby and sapphire. 


Diamonds are also very tough, meaning that they do not easily break, chip or crack. And even more interestingly, they are extremely resistant to heat and chemicals: it would take a temperature of at least 720° Celsius in air, or 850° Celsius in a vacuum, to burn a diamond; and sulphuric and hydrochloric acids, which are capable of completely dissolving the skin and bones of a person, have no effect at all on diamonds (in fact, these acids are actually used to clean the oil and dust off polished diamonds after they have been cut). 



This question had been unanswered till the end of the seventeenth century. 

Even the relationship to carbon was suspected.

In 1694, two Italian academicians had done an experiment on diamond in Florence.  They set up a large burning glass focused on a small diamond and saw it “cracked, coruscate and finally disappear”, leaving a minute quantity of blue ash. But it was the French physicist Babinet, who proved beyond reasonable doublet that a diamond was carbon in exceptionally pure form.           

 One of Lavoisier’s most celebrated experiments was to place a diamond in a bell jar filled with oxygen which rested in a basin containing mercury. The rays of the sun were then focused on the diamond by means of a large burning glass. After the diamond had been consumed, the bell jar was found to contain great quantities of carbonic acid, indicating to Lavoisier that the diamond was composed of carbon. Later experiments by Humphry Davy in England prompted him to conclude that the diamond was composed of carbon and nothing else, a view that was first contradicted in 1841 by Dumas and Strass whose numerous experiments revealed minute traces of other elements notably nitrogen and aluminum. It is these slight impurities that deform the perfect crystalline structure of the ideal diamond and can have a marked effect on the physical properties of a stone. 
It would be an exaggeration to say that not much more is known about the origin of diamonds today, more than two thousand years ago when they were believed to be the splinters of stars. Nevertheless, it is true that there is still no unanimity among geologists about exactly how and where diamond is formed. As late as the nineteenth century, theories about the origin of diamonds had been shaped by the fact that the stones had always been found on or very close to the surface, either in riverbeds or in the beds of the rivers that had dried up ages ago. Even as late as 1869 the Gentlemen’s  Magazine of London reported that a “continental experimentalist” had declared that the intense cold of stellar space disassociated and crystallized carbon from “masses of meteoric nature coursing through space” and caused diamonds to fall from the sky. The editor went on to comment that “the location of diamonds upon the earth agrees much better with the hypothesis of a sky source than an earth source” and that “those cope specimens now attracting so much attention are found on the surface of the ground only it is of no use to dig for them”, still the “continental experimentalist” may well have a point. Diamonds have been found in meteor craters at Novo Urei in south-eastern Russia and at Canyon Diablo in Arizona; although most scientists believe they were created by the heat and pressure of impact and not carried to earth in the meteors.   

It was not until the discovery of the “dry diggings” at Kimberley in 1870, coupled with the determination of the miners to excavate every inch of their dearly bought claims that it became clear that diamonds came from below and not from above. It was also clear that diamond was invariably associated with one particular type of rock and that this rock was only to be found in clearly delineated areas. Since the rock and the diamonds persisted at depth, it was soon suggested that these “pipes” were volcanic in nature and that diamonds had been formed out of carbon under intense heat and pressure deep in the bowels of the earth. They had been forced toward the surface when those long extinct volcanoes had erupted millions of years ago. This strange diamond bearing rock, soon to be called Kimberlite was assumed to be nothing more than solidified lava. But as mining progressed at Kimberley it was discovered that the pipes were not great volcanic funnels plunging into the earth’s core.

A great deal has since been learned from the making of synthetic diamonds and perhaps the most widely accepted current theory is that since diamond forms at pressures and temperatures between 0.5 million pounds per square inch, the formation must have taken place at depths of at least 120 miles, chemical studies pointed to the ultra basic rock peridotite in its molten form as the most likely to have provided the right conditions for the creation of diamond from carbon. The molten of crystallization is assumed to have been long and slow and the theory goes that conditions remained stable for a considerable period as a result of the pressure of carbon dioxide gas below became too great, the balance was changed and the diamond bearing magma was driven explosively towards the surface. On the way, it picked up other rocks and minerals forming itself into the “geological plum pudding”  that we now call Kimberlite, eventually erupting through the surface of the earth and solidifying.

 
Diamonds are made up of pure carbon atoms that exist deep in the ground, exposed to intense heat and pressure over billions of years. Over time, this pressure builds up and forces the diamonds and rocks up toward the surface in a volcanic-like explosion. The explosion creates a very deep, wide hole called a "pipe" into which most of the diamonds settle; these deposits of diamonds are known as primary deposits. Other diamonds are washed away by water or erosion, and often settle into the coastal waters of nearby bodies of water; these are alluvial deposits. These deposits occur in many places around the globe; however, the largest commercial deposits exist in Angola, Australia, Botswana, Namibia, South Africa, Russia and Zaire, which produce 80% of the  world's diamonds. 

Walking through the aisle of a jewelry store, you may not think diamonds are especially rare. But consider this: 250 tons (500,000 pounds) of ore must be mined and processed to produce just one carat of rough diamond. Since a rough diamond typically loses 40% to 60% of its weight when cut, that means that all these efforts are necessary to produce just one of the .50 carat polished diamonds you find in the store's display counters. When you also consider the fact that only about one quarter of all rough diamonds are actually suitable for gem cutting, you can begin to appreciate the rarity and uniqueness of each diamond. 

A quick, fun fact: The first diamond deposits were brought to the surface of the earth approximately 2.5 billion years ago. The most recent deposits are roughly 50 million years old. Your diamond is a truly unique piece of history.  
 
A newly mined rough diamond looks more like a piece of glass washed up on the beach than like the polished gems sold in jewelry stores. Bringing out their beauty requires the skill and art of a trained diamond cutter.
While incredibly precise, computerized machinery is now used in some parts of the cutting process for some diamonds, most of the work is still performed by hand using exacting and meticulous techniques passed down over the generations. 

As a first step, cleaving or sawing is often used to separate the original rough into smaller, more workable pieces that will each eventually become an individual polished gem. Next, bruting grinds away the edges, providing the outline shape (for example, heart, oval or round) for the gem. Faceting is then done in two steps: during blocking, the table, culet, bezel and pavilion main facets are cut; afterward, the star, upper girdle and lower girdle facets are added.
Once the fully faceted diamond has been inspected and improved, it is boiled in hydrochloric and sulfuric acids to remove dust and oil. The diamond is then considered a finished, polished gem.

  What is an "Ideal Cut"?
 
The "Ideal Cut" is a cut based on a specific set of proportions for a round brilliant diamond proposed by gem cutter Marcel Tolkowsky in 1919. While Tolkowsky's original theories presented only one particular combination of proportions for creating the best balance of brilliance and dispersion, today the American Gemological Society recognizes any diamond falling within a narrow range of proportions and finish quality as being an "Ideal Cut" (also called an "AGS 0" or "AGS triple zero").

How does a diamond get from the mines to the stores ?
 
Finding the rough diamonds is only the first step. Once diamonds have been mined and processed out of the 'overburden' (that is, the kimberlite rocks in which they are imbedded), the rough crystals are sorted and categorized according to their size, color, shape and other characteristics. At this point, a diamond can follow one of two routes. 

The most common route is through the channels of DeBeers' Central Selling Organization (CSO). Many people are familiar with DeBeers mainly because of their advertisements and commercials and because of the famous motto that they coined in the early half of the 20th century: "A Diamond is Forever."
While DeBeers' market influence has decreased somewhat over the last few years, they still control the majority of the world's diamond production (an estimated 30% to 40% of annual diamond production). 

The purchasing arm of the CSO not only buys diamonds from member mines around the world; it also finances mining technology for governments which do not have the means to mine their own deposits. Most of what is bought through the CSO is sent to London to be offered to buyers through DeBeers marketing arm, the Diamond Trading Corporation (DTC). The DTC holds ten week-long selling sessions called 'sights' each year. These sights are by invitation only, and only a handful of diamond manufacturers from around the world (called 'sightholders') are allowed to attend. These sightholders may chose to cut the rough diamonds they buy themselves, or they may chose to sell some of the rough diamonds to smaller manufacturers. These smaller manufacturers cut the rough diamonds and sell the polished gems either to jewelry manufacturers (who set the diamonds into finished pieces of jewelry and then sell the jewelry to jewelry retailers), or to diamond wholesalers (who then, in turn, sell the diamonds to diamond retailers). 

In the less common route from mine to market, some independent miners elect not to sell their mine production to the DeBeers cartel. Instead, they offer newly mined diamonds directly to other world buyers. These buyers, in turn, may chose to cut and sell the diamonds themselves, or pass the diamonds along within the industry in a manner similar to that described above.
 
 
The answer depends on whether you are investing in the diamond itself, or in what a diamond represents. 

Diamond prices have been steadily increasing for the past 20 years, and diamonds tend to hold their value. Given this, it is extremely unlikely that diamonds will ever entirely lose their value, in spite of how the market may change in the future. However, no one can predict, with absolute certainty, which way the market will swing and, in general, we do not recommend buying up high-quality diamonds as a main part of a financial/retirement plan.
On the other hand, if you are looking for a source of beauty and a symbol of eternity and everlasting love, there are few objects you can choose that will surpass a diamond's perfection. Diamonds have inflamed man's passions since the first moment at which they were discovered, and their power over our emotions and desires has only grown since then. As a timeless and beautiful gift to yourself or as an emblem of your commitment to another, a diamond is an excellent investment.

What is the difference between a "certified diamond" and a "non-certified diamond"?
 
There is no physical difference between a diamond that is certified and one that is not. A certificate does not change the nature of a diamond in any way. The difference between a certified and an uncertified diamond is that, with the certified diamond, you have tangible, legal assurances as to the particular nature and quality of the diamond you are purchasing. 

A certified diamond comes with a diamond grading report guaranteed by an accredited gem lab. This report assures the customer that the diamond is independently recognized as possessing all the qualities specified by that report. All the diamonds featured in the Diamond Store on our site are certified by either GIA or AGS. When you buy a certified diamond, you are getting a diamond with beauty and pedigree. 

On the other hand, an uncertified diamond has is not accompanied by a diamond grading report, and therefore its stated quality is based only on the word of the seller. 

An uncertified diamond is not necessarily a bad diamond; certainly, it can be as beautiful as its certified counterpart. However, we encourage our customers to buy certified diamonds for the following reasons: 

Shopping for certified diamonds allows you to make an informed choice about your selections, and to comparison shop. You can compare one diamond with a particular weight and quality with other diamonds of similar weight and quality to determine which is the better value. With uncertified diamonds, it is difficult to determine whether the quality assessments of one jeweler will be as stringent and precise as the judgments of other jewelers; that is, not all jewelers may agree about the quality of an uncertified diamond. 

A diamond grading report adds value to a diamond. The quality assessments made by independent labs, such as GIA or AGS, are recognized worldwide. These quality assessments are used by appraisers to determine the insurance or replacement value of your diamond. If you purchase an uncertified diamond, there is no guarantee that the appraiser will appraise your diamond at the same level at which the jeweler who sold it to you did. A quick note on how reports from various independent labs compare with one another: GIA and AGS are considered the industry leaders, and the final word on gem quality, among diamond dealers worldwide. While plenty of other independent labs exist, some are a bit lax in their assessments of diamond quality and do not command the same respect for consistency and quality of grading that GIA and AGS do. For this reason, if you are in the market for a diamond, make an effort to buy only GIA- or AGS-graded diamonds. 

A diamond grading report adds an increased comfort-level to your purchase. Because the quality of your purchase has been independently verified, you can feel assured that you have made a wise purchase and that you have received exactly what you have paid for.

Is it safe to receive a diamond in the mail?
 
Yes and no. It is safe if the diamond jeweler uses insured carriers (e.g., FedEx and UPS) to ship its packages and all shipments are insured for the full value of their contents. 

Before buying a diamond online, find out what the store's policy is in case of lost shipments. A professional diamond jeweler should have no objection to providing either a replacement or a refund. 

History:       
The story of the diamond begins in a remote era the world’s history, lost in the mists of time. For untold ages the diamond lay hidden and unregarded within the earth, until man at last recognized it as the most precious of all nature’s creation and begins to use it for his own delight and benefit. We will probably never know exactly when the  first diamonds were discovered. But we do know that from ancient time until eighteenth century, India was the world’s sole supplier. Although it is impossible to locate the first discovery, there are very early documents that mention the diamond and perhaps explain why man showed such special interest in it. Many histories maintain that the diamond has been known since ancient times.
In Greek literature from very early date the word adamas (which eventually gave its name, via Latin adamus, adamantinus, to the diamond) is often used in sense very close to that of yahalom, being similarly associated with the idea of invincibility. The first known use of the word occurs in the works of the poet. Hesiod, who lived in the eighth century B.C. But nowhere in Hesiod, or in any other writing of that period, is the term applied to a diamond or any other precious stone. For some eight centuries the word adamas was applied exclusively to iron, to describe its unbreakable quality. Not until the first century A.D. was the word used as a noun, by that time, no doubt, designating a diamond. It appears as such in the celebrated Roman encyclopedia, the natural History of Pline the Elder.

India: The first Producer  

It is curious that in all the numerous, lengthy arguments among historians over the origin of diamonds, discussion nearly always centers on the countries that acquired the gems and never on the country that produce them. From ancient times until Brazil entered the picture in the eightieth century, India was the only significant diamond producing country. Until the twentieth century, source for the study of diamonds in India were largely unavailable. In 1905, however, an ancient Sanskrit manuscript was discovered, the Artha Sastra of Kautilya, which may be translated as “The Lesson of Profit”. This remarkable work is basic text providing invaluable detail of the economic and legal history of India in the fourth century B.C. Kautilya was the minister of King Chandragupta Maurya and had helped put him on the throne of the kingdom of Magdha. King Chandragupta, who ruled from about 320 to 298 B.C., was the founder of the Maurya dynasty and may be called the first emperor of India. We know of him also through the Greek Megasthenes, who lived at his court until the discovery of the Artha Sastra, in fact, Megasthenes was our sole source of information on this period. A careful reading of Kautliya’s treatise reveals unquestionably that not only were diamonds known in the fourth century B.C., but they were commodities in a very active trade, were subject to regular taxation and customs duties, and were one of the sources of the royal revenue.

Diamond Found:    

The first undoubted diamond were discovered in India and it was there that the first systematic diamond mining was carried on Jean Baptiste Tavernier, the celebrated French Jeweller and traveller in the East, recorded intensive mining going on in the 1660’s at Kollur near Golconda the legendary fortress city that lent its name to the entire mining area and served as the headquarters of the Indian diamond trade.


 It was at Kollur that the most famous Indian diamond-The Kohinoor, The Great Moghal and The Regent are said to have been found. Another celebrated diamond mining area was further north at Panna and neighbouring villages in the province of Bundelkhand. It is a strange coincidence that the Brazilian diamonds were found just as the supply from India was running down, and that even the Brazilian deposits were nearly exhausted in their turn, huge supplies were discovered in South Africa. It had long been thought possible that diamonds would be found in South Africa. The early Boers were farmers not explorers and they had little interest in geology that not leads them to fertile soil or abundant water. It was not until thirty years later in 1866, that the first known diamond was picked up.

 Everyone knew that diamonds came from India and more recently from Brazil and they had forgotten the skepticism that had greeted the Brazilian finds in the 18th century. The colonial secretary is to have taken the diamond into Cape town., placed his hand upon it and said “Gentlemen, this is the stone on which the future success of South Africa will be built.

 How to choose the Perfect Diamond 
Buying a diamond is one of the most important decisions a couple will make. Choosing the size and shape along with the style of the mounting are important personal choices. Understanding the characteristics that influence the brilliance, beauty and value of diamonds can make your buying experience more enjoyable and more fulfilling. Diamonds are like people—no two are ever exactly alike. Very subtle differences in the internal and external characteristics of each stone, along with subtle variations in color and cutting proportions, have a measurable effect on the value of two diamonds which may appear to be similar. Start with a good jeweler, one who’ll take the time to help you through the 4 Cs—cut, color, clarity and carat weight. Understanding the language of diamonds will put you more at ease in making your selection. The next step should be obtaining a diamond certificate from a reputable independent gemological laboratory. The certificate identifies and evaluates specific characteristics that determine the value of the stone you select.




Diamond Trading:     

The diamond business has been redefined by branding and the fundamentals of advertising, public relations, and marketing - all of which are geared to the downstream retail and consumer jewelry markets with their unique customer segmentation features and demographics. Online access to the multiple brand environment of the diamond business including articles about Lev Leviev & Bulgari - May 2004, the Art of Marketing and Branding Diamonds, and The Case of the Missing Icon - De Beers LV.

Emerging Trends Downstream:
Emerging trends in the global diamond jewelry, fashion, and retailing sectors.

Antwerp World Diamond Center:
Approximately 1,500 diamond offices are located in Antwerp on Hoveniersstraat, Schupstraat, Rijfstraat, and Pelikanstraat.

Natural Diamonds:
The cumulative effect of branding can already be calculated and determined. The next challenge facing the diamond business, trade, and industry is promoting the importance of and supporting the integrity of natural diamonds (and their sources of rough). Private companies, individual diamond exchanges, the DTC, and the World Federation of Diamond Bourses have already started to address the issue.
Brands:
Branded diamonds and jewelry are the hottest topics in the diamond trade today; hearts and arrows, ideal cuts, round brilliants, squares, fancy shapes, fancy colors, modified rounds and fancies, the Regent, Queen of Hearts, Hearts on Fire, the Lazare Diamond, the Leo Diamond, Dream, Prince, Nakshatra, PrincessPlus, Royal Asscher, Lily Cut, Crisscut, cushion cuts, Rand, Cushette, Zales, Princessa, Flanders, Sirius, Tsarina, Lucida, Elara, Tycoon, Escada, Ashoka, Vera Wang, the Regent, the Queen of Hearts, the Eighternity, the Web Cut, and the Radiant Star to name but a few.

Mumbai India's Diamond Capital:
Hundreds of diamond offices are located in the general area of the Royal Opera House near the Roxy Cinema, Mumbai.

Surat  World's Major Diamond Cutting & Polishing Center:

 Surat, is the major diamond manufacturing center. 8 out of 10 diamonds are cut & polished in Surat.

Sightholders: 

 Branded diamonds and jewelry and other sightholder programs have the advantage of support from De Beers and the DTC including a new trademark, the forevermark program, the Diamond Promotion Service (DPS) worldwide, the Diamond Information Centers, J. W. Thompson, and many other added value features and services.

Jewelry Trade Shows:

 The favorite venues for launching a new line of diamond set jewellery or a new branded diamond are the jewelry tradeshows worldwide, including the JCK, the JA New York, the Couture Show, Centurion, Diamonds by JCK, and shows in Las Vegas, Tucson, Mumbai, Tokyo, Bangkok, Basel, Hong Kong, and China.

Bourses:
Offices in diamond exchanges and cutting centers, worldwide including Hong Kong, Antwerp, Ramat Gan, New York, Tokyo, India (Mumbai and Surat), Israel, China, Canada, Russia, South Africa, Dubai, Shanghai, and Moscow trade in both rough and polished diamonds.

Israel Diamond Exchange: 

 Approximately 1,200 diamond companies are located in the Shimshon, Maccabi, Noam, and the Diamond Tower buildings.

Diamonds  Luxury Marketing

Advertising has increased in luxury, business, travel, bridal, fashion, and jewelry magazines including Elle, Maxim, Oprah, Town & Country, Vogue, W, Robb Report, InStyle, and Vanity Fair to name but a few. The bridal market (and the media devoted to it) is considered to be an easy entrance course into the world of branding and brands, because the curriculum stays the same and the class changes on a regular basis.
THE 4 Cs
Cut
Cut actually means two things: the shape of the diamond (round, marquise, pear, oval, heart, emerald, princess, radiant, etc.) and the proportions of the stone. When a stone is cut to good proportions, light is reflected from facet to facet, then dispersed through the top. The better the cut, the greater the sparkle, brilliance and fire of the stone.
Color
Most diamonds look colorless. But there are subtle shade differences that range from colorless to yellow/brown. Diamonds are graded on a color scale that ranges from D (colorless) to Z (yellow/brown). Diamonds with no hint of color at all are extremely rare and are therefore, most valuable. Most gem quality stones appear to be colorless, but they usually have at least a hint of color.
Clarity
Almost all diamonds contain a combination of internal and external characteristics called inclusions and blemishes. Normally, they are too minute to be visible without powerful magnification. Some are even so small they require great skill and time to locate. The number, type, location, visibility and color of inclusions determines a diamond’s clarity and may influence its value.
Carat Weight
Like all precious stones, the weight or size of a diamond is measured in carats. A one carat stone is equal in weight to one hundred smaller units called “points.” Therefore, a fifty-point diamond, for example, is the same as a half carat. Carat weight is the most obvious factor in determining a diamond’s value, depending on the quality of its cut, clarity and color.

Grading Colored Stones
Gemstones are the most fascinating natural objects on earth. Ancient historical records show that primitive peoples adorned themselves with gems and believed that gems had magical powers. Some societies even used powered gems for medicinal purposes! The classification of gems in ancient times was mainly associated with color. In other words, all red stones were once called "ruby," all green stones were called "emerald," and all blue stones were called "sapphire." Today people wear gems for many different reasons, including fashion, sentiment, and prestige. As gems became associated with money, the need for accurate identification grew.
The introduction of manmade gems and imitation materials in the 1800's created an urgent need for experts who could separate the genuine from the fake. The invention of the first cultured pearls and green-glass emerald imitations in the early 1900's further created need for gemological expertise. Today virtually all gemstones, including diamonds, have a number of manmade counterparts and imitations.
The 4 C's of Colored Gemstones
Colored stones are graded in a similar way to diamonds. Color, clarity, cut, and carat weight are the main value factors. The difference is that these factors are evaluated and weighted somewhat differently than in diamonds. Diamonds are assigned very precise grades for color, clarity, and cut. In colored stones, color is the main consideration. Unlike with diamonds, a minor clarity difference rarely affects the price of colored stones.
Color:
Color in gemstones normally results from the presence of small amounts of trace elements. Some of these coloring agents are an essential part of the gem's composition, while some are introduced as an extra element when the gem is forming in the earth. Regardless, these elements are responsible for the amazing variety of colors we see in the many different gemstones. Even diamonds appear in virtually all colors of the rainbow. Generally, the more pure and intense the color, the more desirable and more valuable the stone will be. Once again, a top color is more important than a top clarity.
Clarity:
The internal purity or clarity of a colored stone is secondary to the color quality. Clarity characteristics are often a beautiful part of a colored stone--and a key to identification. Collectors even value some colored stones for unusual inclusion scenery. In fact, inclusions can actually increase the desirability and value of certain colored stones. They do this by creating what is called "phenomena." An example of highly valued and beautiful phenomena in colored stones is the star appearance in sapphires and rubies, which results from the presence of intersecting "needles" of the mineral rutile. The cat's eye phenomena in tiger-eye quartz is the result of a similar condition, except the inclusions are lined up in a parallel manner. The value of certain colored stones, however, can be diminished by the presence of inclusions, when those inclusions are so numerous that they interfere with the passage of light through the stone and make it look cloudy.
Cut and shape:
Colored stones are cut into a wider variety of shapes and proportions than diamonds are. Where the round brilliant-cut is most popular for diamonds, other shapes are better suited to show off a colored stone's beauty, such as oval, cushion, pear, marquise, emerald cut, cabochon, mixed-cut, trapezoid, and tablet. Each cut is chosen to show off the best color and preserve the most weight from a colored stone. Colored stone proportions also differ radically from those of a well-cut diamond. The bulk of a colored stone may be on the bottom where it has the best chance of returning the most brilliance and best color to the viewer. Certain colored gems look better in some cuts than in other. For instance, the majority of fine quality emeralds are cut in the traditional emerald cut shape. Opals are always cut with a smooth curved top (en cabochon). Fine quality rubies and sapphires are normally cut in oval or cushion shapes.
Carat weight:
The weight of diamonds and colored stones is expressed in carats. One carat consists of 100 "points" and is equal to 0.200 grams.

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