HISTORY OF DIAMONDS

ABOUT DIAMONDS

Diamonds have been a source of fascination for centuries. They are the hardest, the most imperishable, and the brilliant of all precious stones. The word "diamond" comes from the Greek word adamas, meaning "unconquerable".
A diamond is a transparent gem made of carbon, one of the earth's most common elements. The formation of diamonds began very early in the earth's history, when the condensation of solid matter into a sphere caused the centre of the planet to become subjected to incredible extremes of temperatures and pressure.
It was these conditions that caused deposits of carbon to begin to crystallise deep in the earth. As the earth's surface cooled, volcanic activity forced streams of magna (liquid rock) to the surface, carrying with it the diamond crystals. Later, the diamond-bearing rock hardened, encasing the diamonds in vertical volcanic "pipes".
But not all diamonds are found where they first came to the surface. Subsequent erosion of the topsoils over millions of years washed some of the diamonds into streams and rivers, and sometimes as far away as the sea. It is highly probable that they were first discovered in areas such as these, far away from their original location.
The atomic structure of a diamond gives it the property of being the hardest substance known to man, natural or synthetic. The diamond is thousands of times harder than corundum, the next hardest substance from which rubies and sapphires are formed. Even after many years of constant wear, diamonds will preserve their sharp edges and corners when most other stones will have become worn and chipped.
However, many people expect a diamond to be unbreakable. This is not true. A diamond's crystal structure has "hard" and "soft" directions. A blow of sufficient force, in a very exact direction, can crack, chip, split or even shatter a diamond.

From myths about valleys of diamonds protected by snakes, to the production of millions of carats in rough diamonds each year, the history of diamonds is one of mystical power, beauty and commercial expertise.
Early History  The first recorded history of the diamond dates back some 3,000 years to India, where it is likely that diamonds were first valued for their ability to refract light. In those days, the diamond was used in two ways-for decorative purposes, and as a talisman to ward off evil or provide protection in battle.
The Dark Ages The diamond was also used for some time as medical aid. One anecdote, written during the Dark Ages by St Hildegarde, relates how a diamond held in the hand while making a sign of the cross would heal wounds and cure illnesses. Diamonds were also ingested in the hope of curing sickness. During the early Middle Ages, Pope Clement unsuccessfully used this treatment in a bid to aid his recovery.
The Middle Ages During the Middle Ages more attention was paid to the worth of diamonds, rather than the mystical powers surrounding them. Due to the heightened public awareness of the value of diamonds, mine owners perpetuated myths that diamonds were poisonous. This was to prevent the mineworkers swallowing the diamonds in an attempt to smuggle them out of the mines.
The popularity of diamonds surged during the Middle Ages, with the discovery of many large and famous stones in India, such as the Koh-I-Noor and the Blue Hope. Today India maintains the foremost diamond polishing industry in the world.
As the Indian diamond supply dwindled, smaller finds occurred in Borneo and Brazil, but these were not sufficient to meet the ever-increasing demand for diamonds. The mid-nineteenth century discovery of diamonds near the Orange River in South Africa sparked the world's biggest diamond rush, and helped to satiate the world's increasing appetite for diamonds.
Recent Times  During the mid-nineteenth century, diamonds were also being discovered in eastern Australia. However, it was not until late 1970's, after seven years of earnest searching, that Australia's alleged potential as a diamond producer was validated.
On October 2nd 1979, geologists found the Argyle pipe near Lake Argyle: the richest diamond deposit in the world. Since then, Argyle has become the world's largest volume producer of diamonds, and alone is responsible for producing over a third of the world's diamonds every year.

TYPES OF DIAMONDS

Pink Diamonds  The pink diamond is the world's most rare and valuable diamond.The Argyle mine is the world's foremost source of unrivalled intense pink diamonds, producing 95% of the world's supply. However, an extremely small proportion of Argyle Diamonds production is Pink colour, in fact less than one tenth of 1% is classified Pink.
The legend of Argyle pink diamond has grown over the past ten years. At the 1989 Christie's auction in New York a 3.14 carat Argyle pink sold for $1,510,000. Privately, Argyle has sold pink diamonds for up to $1 million a carat.
For years the white diamond was considered the world's most beautiful diamond, until the discovery of the Argyle mine heralded the arrival of the Argyle pink diamond. Never before had pink diamonds displaying such intense shades of colour been seen. The pink diamonds of India, Brazil and Africa were characteristically light in colour and paled even further when placed beside the intensely pink Argyle diamonds. The natural colour diamonds have in fact been around as long as the classical whites but in much smaller quantities and never in great demand.
The Argyle pink diamond comes in shades ranging from delicate pastel rose to robust raspberry and full-blooded purple-reds. The prices per carat are determined by the intensity of colour. Argyle selects only its most vibrant pink diamonds for polishing at its head office in Perth. There, the stones are polished in a wide range of cuts, such as round brilliant, marquise, oval and pear, to enhance their natural beauty. Polished pink diamonds are available in the same size ranges as traditional commercial sizes.
Once a year, Argyle Diamonds issues a special release of outstanding pink diamonds that are sold by special bids in the international and invitation-only, Pink Diamond Tender.
White Diamonds  White diamonds are produced by mines all over the world in a wide variety of shapes and sizes.The white diamonds recovered from the Argyle mine are particularly brilliant and of high quality.
White diamonds with secondary pink colour The Argyle mine also produces white diamonds with secondary pink colour that command a higher price per carat. In an effect similar to that described of pink champagne diamonds, the white diamond will display slight to bold flashes of pink when viewed from the top. A higher price is commanded for pink secondary colour depending on its depth and strength, because pink is one of the most rare colours found in diamonds.
Champagne Diamonds Champagne diamonds are naturally coloured diamonds that are produced in a wide range of colours from light straw to rich cognac. The 4C's of colour, cut, clarity and carat weight apply to coloured diamonds just as they do to colourless diamonds except the intensity of colour, not lack of it, plays a greater part in the valuation.
Argyle Diamonds created the following scale specifically for champagne diamonds. The diamonds are graded on a C1-C7 colour scale. C1 and C2 represent light champagne, C3 and C4 medium champagne, and C5 and C6 dark champagne. The fancy cognac diamond is graded C7.
Pink Champagne Diamonds Attractive champagne diamonds with secondary pink colour are also available and command a higher price per carat than champagne diamonds. These stones display slight to bold flashes of pink in their fire. Argyle Pink Champagne Diamonds are available in three ranges of shades, from light pink champagne to medium and dark pink champagne. As pink is one of the rarest colours found in diamonds, even secondary colours demand a higher price depending on depth and strength of colour.
Yellow Diamonds  Fancy yellow diamonds come in a broad range of shades ranging from light yellow to a rich canary colour. A limited quantity of fancy yellow diamonds is recovered from the Argyle mine.
Blue Diamonds Fancy blue diamonds are available in a wide range of shades, from the blue of the sky to a more "steely" colour than sapphire. Limited quantities of fancy blue diamonds are recovered from the Argyle mine.
Green Diamonds Fancy green diamonds are also available. Usually, penetration of the colour is not very deep and is often removed during the fashioning of the stone. A limited quantity of fancy green diamonds is recovered from the Argyle mine.
Diamond Simulants Cubic Zirconia Cubic Zirconia (CZ) is the most commonly encountered diamond simulant. All commercial CZ is formed in laboratories however, it is also found in nature. In both its synthetic and natural forms, CZ is colourless but colour can be introduced. A thermal pen tester can quickly and easily detect CZ. Synthetic moissanite  Synthetic moissanite is a new diamond simulant to join the long list of products that imitate diamonds. Although moissanite is being marketed as a new unique, synthetic gemstone, some of its properties are close enough to those of diamonds to lead to confusion in the trade. Natural moissanite was first identified in a meteorite crater at the beginning of the twentieth century however, most is produced synthetically as natural moissanite is very rare. Chemically, it is 'silicon carbide', also known as 'carborundum', which is widely used for abrasive purposes and for use in the electronics industry. Synthetic moissanite is a diamond simulant like Cubic Zirconia however, it can be passed as a diamond by the widely used thermal pen testers because it has similar thermal characteristics to diamonds. However, it can be easily identified by other methods. MINING DIAMONDS Of all the diamonds mined in the world each year, less than half are gem quality; the rest fall into two other main categories known as near-gem quality and industrial quality diamonds. Gem quality diamonds display a high standard of excellence in quality and are used in jewellery. The clarity of these diamonds ranges from flawless through to visible inclusions. Near-gem quality diamonds represent those stones of a quality between gem and industrial, that in fact can be used as either depending on the individual stone. These stones have clarity grades ranging from visible inclusions through to industrial. Industrial quality diamonds are low quality or badly included stones and are suitable only for industrial use; for example, they are used in dentist's drills and earthmoving equipment. Diamond Mining Diamonds are recovered by way of pipe or alluvial mining. Pipe Mining Pipe mining refers to the extraction of diamonds from volcanic pipes. Typically, a very large area has to be covered. An average of 250 tonnes of ore must be mined in order to produce a one-carat gem quality polished diamond. In most countries, a diamond pipe mine is composed of kimberlite, or blue ground. Initially kimberlite is dug from the surface of the pipes in rough opencast mining. Once the surface deposits have been exhausted, shafts are sunk into the ground at the edge of the pipes, and tunnels are driven into the deeper parts of the pipes. After the diamond-bearing rock is brought to the surface, it is then transported to a screening plant where the diamonds are separated from the host rock. Alluvial Mining This process involves the extraction of diamonds from riverbeds or ocean beaches. Millions of years ago, at the time the diamond pipes were formed, some diamonds were weathered out of the pipes and carried great distances along rivers and even into oceans. In order to extract these diamonds from beaches, a wall is built to hold back the surf. Up to 25 metres of sand is bulldozed aside to reach the diamond-bearing level. Once reached, the diamond-bearing earth is removed and transported to screening plants. Diamond Cutting and Polishing The history of diamond cutting and polishing has its origins in India, where it was discovered a long time ago by Indian lapidaries that a diamond could be made to glisten simply by grinding another diamond against it. Nowadays the diamond and its powder play an important role in the cutting and polishing of diamonds. Over time modern machinery has replaced traditional diamond cutting tools. Diamond cutting and polishing requires anywhere from several hours to several months to complete. During this process, a diamond will lose on average half of its original weight. Diamond Cutting As every diamond is different, a stone must first be carefully examined by the cutter and then marked for cutting. Of all the cuts, the most popular is the round brilliant because of its ability to give a stone the greatest possible brilliance and fire with the most minimal amount of weight loss. The following cutting and polishing procedures uses the round brilliant cut as an example. The rough diamond is divided into two parts by sawing or cleaving. Most stones are sawn across the "grain" (visible evidence of the diamond's crystal structure) by a paper-thin metal disc coated with diamond dust revolving at high speed or by laser. The stones that are marked for cleaving are split along the grain by a single blow from a steel blade. After cleaving or sawing, the corners of the diamond are rounded off by a process known as bruting or girdling (only round brilliant cuts require this step). The stone is cemented into a "lathe", a holder that fits on a turning shaft. Another diamond is cemented to the end of a long rod held under the bruter's arm. As the lathe rotates, the two diamonds are brought together and grinded to shape. Diamond dust is produced from this action and is used in further sawing and faceting. The brilliant now has a girdle-a sort of rim at the widest part by which it is usually set. The size or position of the girdle should not change throughout the rest of the diamond cutting process. Diamond Polishing  The polishing of the diamond begins; one by one, facets will be ground on to the stone. A facet is the tiny plane or surface that traps the light and makes a diamond sparkle. Most diamond cuts have 58 facets. The facets are applied to the diamond on a "turntable", made of porous iron, which has been coated with diamond dust and oil. The diamond is set into a holder and held against the turntable as it revolves at a very high speed. A diamond has been cut well when its facets are clean, sharp, and symmetrical, and the proportions above and below the girdle are correct. A diamond is correctly proportioned when one-third of the total weight of the gem is above the girdle and two thirds below. A well-cut diamond will be fiery, brilliant and beautiful. VALUING DIAMONDS The quality and value of diamonds are measured by four characteristics known as the 4C's. The 4C's relate to a diamond's cut, colour, clarity and carat weight. The quality of a diamond is measured by its cut, colour and clarity. The carat weight measures the size of the diamond. Of all the 4C's, cut is the characteristic directly influenced by man; colour, clarity and carat weight are all dictated by nature. Cut A diamond in its natural, uncut state is described as a "rough diamond". Its natural appearance so resembles a glass pebble that most people would pass it by without a second glance. It is the skill of the diamond cutter that unlocks the brilliance for which diamonds are renowned. If two identical diamonds are placed side by side and one is less brilliant and fiery than the other, the fault lies in the cutting. Such a stone cannot demand as high a price as a well-cut diamond. It is important to distinguish between cut and shape. Some of the more popular shapes of diamonds include Round Brilliant, Oval, Marquise, Pear, Heart and Emerald. Within each of these shapes, however, it is the cut that determines the quality of the stone. For example, most diamonds are cut with 58 facets, regardless of their shape. Colour  A diamond's colour is one of the most important factors in determining its value. The nearer a white diamond is to being absolutely colourless, the more rare and valuable it is. The graduations in colour are so subtle that intricate international grading scales have been devised. Diamonds are graded into categories defined by letters. The colour range from exceptional whites (categories D, E and F) to tinted colours (categories M to Z). The best way to pinpoint a diamond's true colour is to place it next to another diamond that has previously been graded. There are also fancy coloured diamonds and these are graded according to their intensity of colour, not lack of it. There are a variety of reasons for diamonds to be coloured. The most common causes, or suggested causes, for the colours yellow, green, blue, brown and pink are described below. Yellow: When nitrogen combines with the diamond crystals during the formation stage it causes a surplus electron in the bonding. This surplus electron absorbs blue light, thus giving off a yellow colour. Yellow diamonds also occur when aggregates of three nitrogens combine and cause surplus bond. Blue: The elements of boron may also be substituted within a diamond during its formation. Boron absorbs red light, hence in the absence of nitrogen, diamonds containing boron are blue in colour. An example of a diamond containing boron is the famous Blue Hope diamond. Diamonds containing boron also exhibit unusual electrical properties and are semi-conductive in nature. Hydrogen is another impurity that, in high quantities, can cause grey or blue colouring in diamonds. However, these diamonds are not semi-conducting. Green: A vacancy in the regular lattice of atoms within a diamond results in a green colouring. Carbon atoms being knocked out of their regular position by other particles cause vacancies. The depth of colour usually extends about 2mm below the diamond's surface. At extremely high temperatures the vacancies can become mobile and can combine with nitrogen to form other colours such as mauve, orange, blue or gold. Brown: It has been suggested that dislocations in the regular lattice of atoms, caused by severe forces deep in the earth, may be responsible for the brown colouring of champagne and cognac diamonds. The dislocated bonds may affect the light wavelength, thus producing a diamond which is coloured, but which contains no impurities. Pink: It has also been suggested that combinations of dislocations, vacancies, and non-nitrogen impurities cause the much sought-after colouration in pink diamonds. However these theories are still being developed. Clarity During the formation of a diamond it is possible for minute particles of non-crystallised carbon or non-diamond crystals to be caught within the diamond. These imperfections are called inclusions and provide each individual diamond with unique characteristics.Inclusions may not always be visible to the naked eye, however they do interfere with the passage of light through the diamond. Therefore the fewer inclusions a diamond has, the more valuable it is. Like colour, clarity is also categorised using international grading scales. The categories of clarity are based upon the number, size and position of the inclusions within the diamond. Gradings range from flawless, and internally flawless, through very small and small inclusions, to imperfect. The clarity gradings are described as follows: FL Flawless No internal or external blemishes when examined under a 10x microscope.Diamonds in this category cannot contain internal graining that is reflective whitish, coloured,or which significantly affects transparency. IF Internally Flawless No internal inclusions but minor surface blemishes which cannot be removed with polishing. That is, characteristics such as surface grain lines, natural and extra facets on the crown. Blemishes that can be removed by minor repolishing separate the internally flawless from the flawless grade. VVS1 VVS2 Very, Very Slightly Included Minute inclusions, such as reflective internal graining, difficultto locate using a 10x microscope VS1 VS2  Very Slightly Included Small inclusions, such as small included crystals which are visible using a 10x microscope. SI1 SI2 Slightly Included Inclusions that can be seen easily under a 10x microscope,and may also be seen with the naked eye using a white background. Inclusions in these diamonds cannot be seen through the crown of the diamond. I1 Imperfect 1 Inclusions can be seen with the naked eye, and are quite obvious under a 10x microscope. I2 Imperfect 2 Inclusions can be seen with the naked eye, and may interfere with transparency and brilliance. I3 Imperfect 3 Dark inclusions which are very noticeable to the naked eye, and which interfere with transparency. Diamonds in this category may contain cleavages that are likely to become worse with wear. Carat A carat is the unit of measure used to determine the weight of a diamond. The term "carat" is derived from the original method of using carob tree seeds to weigh diamonds. One seed from this tree was equivalent to one carat. The actual weight of one carat is now established at 0.2 grams. To assist in accurately describing the weight of diamonds each carat is divided into 100 points. Diamonds of less than one carat in weight are known as "pointers". For example, a 0.15 carat diamond would be called a "15 pointer". Diamonds are usually weighed prior to setting for more accurate measurements. Diamonds are priced per carat, according to their size and quality. Although the carat weight of a diamond is indicative of its size, it is not necessarily indicative of a diamond's quality. Therefore, where two diamonds have the same carat weight, the one of better quality will command a higher price per carat. CARING FOR YOUR DIAMONDS Diamonds need caring to keep them looking at their brilliant best. They should be cleaned at least once a month to keep away the "dullness" that can be caused by skin oils, soap, cosmetics and even cooking grease. The only substance that does not stick to a diamond is water. A clean diamond will reflect better light. There are several ways of keeping diamond jewellery clean. The detergent bath is performed with a small bowl of warm suds using any mild liquid detergent. Immerse jewellery pieces in the suds and brush gently with a tooth brush. Rinse under warm running water and pat dry with a soft, lint-free cloth. The quick dip method uses one of the liquid jewellery care products available. Follow the instructions on the kit. The latest jewellery-cleaning device is the sonic jewellery cleaner. It is electronically operated and comes with its own solution and directions. Some extra helpful hints to keep diamond jewellery looking at its best. It is better not to wear diamond jewellery when doing rough work or the dishes. Despite the durability of a diamond, it can be chipped by a hard blow along its grain. Take care when doing the housework, not to let diamond jewellery come into contact with chlorine bleach, as it won't harm the diamond but can pit or discolour the mounting. When placing diamond jewellery in a jewellery case, be sure to wrap them individually as they can easily scratch each other as well as other gem jewellery. Be sure to take all types of precious mounted jewellery to a jeweller at least once a year to check for loose settings and signs of wear. THE AUSTRALIAN DIAMOND INDUSTRY Australian Argyle Diamonds are internationally reowned for their unique brilliance and stunning array of colours. Unearthed in the rugged Kimberley region in the far north of Western Australia, Argyle Diamonds thrill in shades of exotic pink, sparkling champagne, rich cognac and dazzling white. From the rare pink diamond to the classic white and natural champagnes, Argyle Diamonds are firing the world's imagination. And why shouldn't they? The Argyle Diamond Mine is the world's biggest producer of natural diamonds and contributes approximately one-third of the world's natural supply. Discovery Of The Argyle Diamond Mine The Argyle diamond story has its origins in the early 1970s, when one of the world's most significant find of diamonds was made at Smoke Creek in the remote north of Western Australia, over 2000 kilometres from Perth, the state capital. Although significant, it is certainly not the first discovery of diamonds in Western Australia. Diamonds had been recovered in the Pilbara region as far back as the 1890s but the primary source of any of these diamond finds had never been located. The key was time and patience. For decades, geologists had known that a major source of diamonds existed in Australia, but is wasn't until 1972 that their work had identified the Kimberley region as being the most likely location. A joint venture was formed. Geologists spend the next seven years patiently searching the region to discover the Argyle diamond deposit, tantalised by new clues and frustrated by dead ends. The geologists received their biggest encouragement yet with the Ellendale Prospect in 1977. A number of diamond-bearing kimberlite pipes were discovered in Ellendale, located near Derby. However, the evaluation of the Ellendale Prospect showed it to be uneconomical. It wasn't until October 2 1979, that geologists were literally standing on top of the richest diamond deposit in the world. They had pinpointed the Argyle Diamond pipe. The discovery was made while working in Smoke Creek near the awesome Lake Argyle, a man-made dam covering some 720 square kilometres. Geologists found several stones in the creek bed and back tracked along the course finding more diamonds as they went until they climbed high into the range and before long were standing on the Argyle diamond pipe. What followed was an exclusive programme of drilling, sampling and evaluation. In 1982 the joint venture partners decided to develop a mining operation. The Argyle Diamond Mine  In 1983, construction work began on the main open-cut mine and process plant. In the meantime, diamonds began to be recovered by an alluvial plant at Smoke Creek and Limestone Creek. Some 15 million carats of alluvial diamonds had been recovered by the time the main Argyle plant was commissioned in 1985. Argyle Diamond Production  The Argyle diamond mine has firmly placed Australia on the top as the world's biggest producer of diamonds in terms of volume. As well as being Australia's only major diamond producer, the Argyle diamond mine is also one of the most technologically advanced mines in the world. Since its inception, annual production has steadily increased from 29 million carats in 1986, the mine's first full year of production, to 40.9 million carats in 1993. The average annual production since 1994 has been over 35 million carats. Every year the Argyle diamond mine is responsible for producing more than a third of the world's total annual supply of diamonds. The average annual production now totals over 35 million carats. The Argyle diamond mine yields approximately 45 per cent near gem quality, and 50 per cent industrial quality diamonds. The remaining 5 per cent is made up of gem quality diamonds and yields the rare and highly valued pink diamonds, as well as the range of sparkling champagne and rich cognac diamonds. Argyle Diamond Mining  The Argyle diamond mine covers an area of 45 hectares. The diamonds are recovered from the main pipe as well as from, to a lesser extent, alluvial deposits in nearby Smoke and Limestone Creeks. The Argyle diamond pipe is a linear body, 1600 metres along and varying in width from 150 to 600 metres. In addition to being the world's biggest diamond producer and only reliable supply of intense pink diamonds, the Argyle diamond mine is unique in a third way: the diamonds are recovered from a host rock call lamproite, not kimberlite which is the traditional host. Argyle's pipe mining operation involves the removal of the diamond-bearing lamproite ore by open-cut mining techniques. The ore is dislodged by blasting and then loaded by excavators into 120-tonne dump trucks. The ore is then transported to the processing plant where the diamonds are extracted. The processing techniques are purely physical and involve crushing, scrubbing, screening and gravity separation of the diamond-bearing ore. Final diamond recovery is achieved by the use of x-ray sorting machines. The machines can detect and remove diamond material because the diamonds fluoresce under x-ray. No chemical treatment is included in the process with the exception of a final acid cleaning of the diamonds. Alluvial mining was discontinued in late 1985, then resumed in 1989. The diamonds recovered are included in the mine's overall annual production. The rough diamonds are transported to Perth for sorting and sale. Argyle DiamondsArgyle Diamonds fall into three main categories: pink, champagne, and white diamonds. The 4C's guide to quality and value applies to coloured diamonds just as it does to white diamonds. However, coloured diamonds are graded for their intensity of colour, not lack of it. Argyle diamonds have two very unique and outstanding features: they are harder than other diamonds and may fluoresce blue under ultra-violet light. The hardness factor of Argyle diamonds results from its unusual atomic structure. Although all diamonds share the same atomic structure, the atoms of Argyle diamonds are bonded together in more complex arrangements. This complex structure is also one of more the major reasons for the deep colours of the Argyle product mix, especially the champagne and pink diamonds. Around 70 per cent of the Argyle yield fluoresces blue under ultra-violet light; a day with high U.V levels will make an Argyle diamond dance and dazzle with lovely blue flashes! The huge diamond shipments from the Argyle Mine are sorted at the Western Australian capital of Perth, the headquarters of Argyle Diamonds. The modern cutting and polishing facility is also located here however, only top quality gems from the mine are polished at this facility. Diamond Sorting  Upon reaching Perth, the rough diamonds are sorted. In order to deal with the huge volume of diamonds, Argyle Diamonds has developed new technology. Sorting begins mechanically: the first size sorting of rough diamonds takes place through a series of mechanical sieves. After sieving, the smaller stones are sorted according to colour and shape by sophisticated equipment at the machine sorting area. However, final valuation of the diamonds can only be made by the human eye despite these advances in technology. Each individual stone is examined by diamond sorters who base their decision on clarity, size, shape and colour. Argyle retains its best quality gems for cutting and polishing. Diamond Polishing Argyle Diamonds carefully selects the best quality diamonds for polishing within Australia or by overseas cutting centres. Australian Production Argyle Diamonds began polishing diamonds in 1984. Its Perth processing centre is the first of its kind in Australia. Australian production is staffed by highly-trained crafts-people who employ a combination of traditional methods and modern equipment to unlock the brilliance of rough stones. Argyle uses advanced technology in the form of laser devices, automatic bruting and computerised polishing equipment. The polished stones are then sold in Australia, through a network of exclusive Australian jewellers, as well as overseas through Argyle's representative offices in Antwerp, Belgium and Bombay, India. Overseas Production Argyle Diamonds also sends a proportion of its rough diamonds, especially those in smaller sizes, overseas for polishing.  GLOSSARY OF TECHNICAL TERMS Acidising: refers to the treatment of diamonds with acids (usually hot) to clean them after mining or after cutting, particularly to remove oxides or polishing residues from surface fissures. A jour : is a type of diamond mount that exposes the pavilion to the light and is used in most modern mounts, unlike earlier closed settings. Baguette: refers to a diamond cut in the shape of a narrow bar, sometimes tapered at one end. It was named after the long French bread loaf. Baton: is another name for a baguette. Bedrock: is the solid rock found under deposits of gravels, silt, sand, soil, etcetera. Bezel facets: occur when the cross-cutter makes the four top corner facets into eight. Bicycle tyre: refers to a thick girdle. Blocking: is putting on the 16 main facets by the cross-cutter. Blue ground: is the miner's name for the unoxidised kimberlite in a pipe or other kimberlitic deposit. Blue-white: is a confusing term often wrongly applied. A blue-white stone should have a faint tinge of blue, even though the description is usually intended to mean colourless. Sometimes it is even applied to stones with a faint tinge of yellow. Boart: is a very low-grade diamond suitable only for industrial use. It is also spelt bort, boort, and bortz. Brillianteerer: is the skilled person responsible for the final stages of putting on and polishing the 40 facets after the cross-cutter's work. It is also spelled brilliandeer. Brilliance: is the intensity of the white light when a diamond is looked at in the face-up position. Bruting: is another name for cutting to fashion the girdle outline of a brilliant cut. Calibré cut: refers to stones that have been cut to standard dimensions for easy setting into standard mounts. Carat: is the standardised unit of weight for gemstones. One carat is equal to 0.20 of a gram. Clean: is used to describe a diamond that has no readily visible inclusions, grade SI and above. Cleavage: refers to the tendency of a diamond to split along the grain parallel to one of its octahedral faces. It is also a term applied to rough diamonds that have at some time been cleaved from a larger stone. Cleaver: is the skilled person who cleaves a diamond into two parts. Closed culet: is the sharp point at the bottom of the pavilion of a brilliant cut, or knife edge on an emerald-cut stone. Cross-cutter: is the skilled person who grinds and polishes the first 16 facets on a diamond. Crown: is the upper part of a polished stone above the girdle. C.S.O.: is the Central Selling Organisation which distributes about 80 per cent of the world's rough gem quality diamonds. Culet: refers to very small facet on the bottom of the pavilion, parallel to the table. It is also spelled collet and culette. Cut: is the shape into which a rough diamond is cut and polished. Cutter or bruter: makes the rough diamond round before it is faceted. Diamond paper: is another name for the parcel paper. Diamond parcel paper: is the specially folded paper in which a diamond is or diamonds are held for carrying, or transporting. Dispersion: describes the way a diamond breaks up a ray of white light into colour. Dop: refers to the holder used for a diamond that is being polished. A diamond is held in a solder dop by solder and in a mechanical dop by metal jaws. Extraction: describes the process of removing diamonds from concentrate. Extra facet: is an additional small facet usually applied to remove a small blemish most commonly on or near the girdle. Extra facet: is an additional small facet usually applied to remove a small blemish most commonly on or near the girdle. Faceted girdle: refers to a girdle on which small facets have been polished to improve the brilliance of the diamond. Face up: is the position of a diamond with the table of the stone facing the viewer. Fancies: are attractively coloured diamonds. Fancy: is a diamond of an attractive colour other than white that is suitable for gem use. Fire: refers to the flashing colours seen when a suitably cut diamond is moved, resulting from its dispersion. Flute: is a thin paper used to line the inside of a diamond parcel paper. Full-cut brilliant: is the correct name for a brilliant-cut diamond with 56 facets plus table and culet. Girdle: is a sort of rim at the widest part of a diamond by which it is normally set. It is the resulting circumference of the adjoining crown and pavilion angles at the widest part of the stone. Girdling: describes the way a rough diamond is rounded. It is also another name for cutting and bruting. Grader: is the skilled person who separates polished diamonds into sizes and quality grades by clarity, colour, and accuracy of cut. Grain: is a name used by cutters and polishers to describe the visible evidence of the crystal structure of a diamond, and will usually determine their procedure. Loose diamond: is an unmounted, polished diamond. Loose diamond: is an unmounted, polished diamond. Lustre: refers to the quality of a surface in reflected light. The lustre of a diamond is usually described as admantine lustre. Mêlée: are rough stones and shapes under two carats and used loosely for small polished diamonds. Mixed-cut: is the mixing of two different cuts for one diamond, such as a brilliant cut crown and step-cut pavilion. Mount or mounting: is the part of jewellery into which a stone is set. Natural: is part of the natural surface of a rough diamond left on the girdle by the cutter striving for maximum weight retention. Navette: is another name for a marquise. Near-gem: is a quality of rough diamonds between gem and industrial. Octagon: word describes the process of adding the eight main facets to the top and bottom of a stone, which makes its table octagon-shaped. Open culet: is a larger than normal culet. Open table: is a larger than normal facet. Open cast or open pit: describes mining from the surface. Opening a diamond: means polishing a window on a rough stone to see inside it. Pavilion: is the bottom part of a polished diamond below the girdle. Pipe: refers to a roughly funnel-shaped, usually extrusion of volcanic rock that may or may not contain diamonds. Point: is the hundredth of a carat, therefore 0.72 carats equal 72 points. Polished girdle: refers to a girdle that has been polished but not faceted. Quality: measures the degree of excellence of a diamond by its weight, colour, clarity and (polished) its perfection of cut. Rough: is the name given to diamonds before they are cut. Sawyer: is the skilled person who saw diamonds. Sawable: are the rough diamonds that can be divided by sawing. Scaife: is also spelled scaive or scaif, and refers to the horizontal turntable or grinding table on which a diamond is polished. Scintillation: refers to the flashing and twinkling sparkle of a diamond when it moved under light. A diamond is always more beautiful in motion because its scintillation depends upon the number of facets visible to the eye when the diamond moves. Set: is a diamond or other stone set in a mount. Skin: is the natural surface of the unpolished diamond. Sorter: is the skilled person who separates rough diamonds into sizes and grades of quality by shape, colour, and clarity. Star facets: are the eight triangular facets around the table of a diamond that make it star-shaped. Table: is the large facet on the top of the diamond's crown. Treated: describes a polished diamond that has been altered to change its appearance, eg by artificial colouration, that is, irradiation. Window: is the facet polished on a rough diamond in order to see inside it.